Open Collections

UBC Theses and Dissertations

UBC Theses Logo

UBC Theses and Dissertations

A study of the ecological relationships and taxonomic status of two species of the genus Calanus (Crustacea:… Woodhouse, Charles D. 1971

Your browser doesn't seem to have a PDF viewer, please download the PDF to view this item.

Notice for Google Chrome users:
If you are having trouble viewing or searching the PDF with Google Chrome, please download it here instead.

Item Metadata

Download

Media
831-UBC_1971_A1 W66.pdf [ 10.66MB ]
Metadata
JSON: 831-1.0093285.json
JSON-LD: 831-1.0093285-ld.json
RDF/XML (Pretty): 831-1.0093285-rdf.xml
RDF/JSON: 831-1.0093285-rdf.json
Turtle: 831-1.0093285-turtle.txt
N-Triples: 831-1.0093285-rdf-ntriples.txt
Original Record: 831-1.0093285-source.json
Full Text
831-1.0093285-fulltext.txt
Citation
831-1.0093285.ris

Full Text

A STUDY OF THE ECOLOGICAL RELATIONSHIPS AND TAXONOMIC STATUS OF TWO SPECIES OF THE GENUS CALANUS (CRUSTACEA: COPEPODA) by CHARLES D. WOODHOUSE, JR. B.A., U n i v e r s i t y of C a l i f o r n i a i n Santa B a r b a r a , 1962 M.A., U n i v e r s i t y of Oregon, 1964 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY i n the Department of ZOOLOGY accept t h i s t h e s i s as conforming to the r e q u i r e d standard THE UNIVERSITY OF BRITISH COLUMBIA A p r i l , 1971 In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, I agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the Head of my Department or by his representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. Department The University of British Columbia Vancouver 8, Canada D a t e / ^ " ^ t P / y / . T h i s t h e s i s p r e s e n t s the r e s u l t s of an i n v e s t i g a t i o n on the r e l a t i o n s h i p s between p o p u l a t i o n s of c l o s e l y r e l a t e d animals un-der apparent sympatric c o n d i t i o n s . The mechanisms found have p a r t i c u l a r a p p l i c a t i o n toward understanding the s p e c i e s problem among members of the free-swimming marine copepod genus Calanus t h a t possess a toothed i n n e r s u r f a c e on the coxopodites of the f i f t h p a i r of swirnming l e g s . The i n v e s t i g a t i o n d e s c r i b e s the morphology, d i s t r i b u t i o n , and g e n e r a l ecology of two forms of toothed Calanus from the f a r e a s t e r n North P a c i f i c Ocean. M o r p h o l o g i c a l d i f f e r e n c e s were es-t a b l i s h e d and used to d i s t i n g u i s h both forms on the o a s i s of l e n g t h , shape of the a n t e r i o r s u r f a c e of the cephalothorax, p r o p o r t i o n a t e d i f f e r e n c e s i n segments of the urosome and f i f t h swimming l e g s , and by the degree of asymmetry i n the f i f t h p a i r of swimming l e g s of males. An a d d i t i o n a l f e a t u r e was the l e n g t h of a s m a l l spine on the f i f t h swimming l e g s of both forms. A g e n e r a l account o f the d i s t r i b u t i o n and ecology of both forms from G l a c i e r Bay, A l a s k a , to the Mexican Border was de-r i v e d from data gathered d u r i n g s e v e r a l l o n g c r u i s e s . The Large Form was found from G l a c i e r Bay, A l a s k a , to Cape Mendocino, C a l i f o r n i a . The Small Form was found from the Mexican Border to the v i c i n i t y of Vancouver I s l a n d , B r i t i s h Columbia. A l o n g the outer c o a s t , the Large Form appeared to be a s s o c i a t e d with P a c i f i c S u b - A r c t i c water t y p i c a l o f the C a l i f o r n i a Current, whereas the Small Form appeared to be a s s o c i a t e d w i t h the warmer more saline water typical of Equatorial Pacific water associ-ated with the Davidson Counter Current. A detailed analysis of the ecological relationships of both forms in a region of overlap was performed in Indian Arm, an inlet near Vancouver, British Columbia. In this inlet, the Large Form was generally associated with the cooler more saline deep water.of the inlet. The Small Form occurred at shallower depths. Overlap between the populations of both forms was lim-ited to Large Form females that rose to shallower depths during part of the year occupying nearly the same portion of the water column as the Small Form population. The yearly cycles of both forms in Indian Arm were shown to be different indicating dif-ferent times of breeding for Large and Small Forms. On the basis of morphology and previous descriptions for toothed members of the genus Calanus, the Large Form appeared to he Calanus glacialis and the Small Form C. pacificus californi-cus. Based on the results of the distributional study and the ecological study, i t was concluded that both forms were behaving as good species since separation of breeding populations both spatially and temporally appeared to be real, and the likelihood of interbreeding appeared to be small. In the classical sense, the two species are sympatric be-cause their ranges overlap, and there is a strong indication that interbreeding occurs infrequently i f at a l l . Association to dif-ferent types of water and differences in yearly cycles appear to be the primary mechanisms that act to maintain the integrity of sympatric species. The vertical as well as horizontal space must be given equal consideration in planktonic studies. Under these conditions, therefore, the toothed Calanus spp. of Indian Arm are allopatric with respect to the water column. Page ABSTRACT • i LIST OF TABLES v • LIST OF FIGURES v i i ACKNOWLEDGEMENTS • i x INTRODUCTION 1 MATERIALS AND METHODS . 12 General sampling procedure 12 Morphology 14 D i s t r i b u t i o n a l Survey 21 E c o l o g i c a l Study . . 2 3 RESULTS 34 Morphology 34 Prosome 34 Headshape 39 Urosome 42 Swimming Legs 49 D i s t r i b u t i o n 6 l Ecol o g y 69 Y e a r l y Presence and D e n s i t y 69 Y e a r l y C y c l e s and P e r i o d s of Breeding 69 A n a l y s i s of Mo u l t i n g Rates 83 P h y s i c a l Environment 85 Mid-Day V e r t i c a l D i s t r i b u t i o n s 93 24 Hour V e r t i c a l D i s t r i b u t i o n s 97 A v a i l a b l e Food IO5 Breeding Experiments.- 107 DISCUSSION • 109 Summary of the D i f f e r e n c e s 1.09 Comparison to. Other S p e c i e s 110 D i s t r i b u t i o n 118 D i s t r i b u t i o n a l E c ology 120 E c o l o g i c a l S t u d i e s i n In d i a n Arm 127 BIBLIOGRAPHY" . 1 4 1 APPENDIX I - Procedure w i t h S t r a t i f i e d P l a n k t o n Net Tows 146 APPENDIX I I - The E x t e r n a l Morphology of•Toothed Calanus spp. from the Waters of Southern B r i t i s h Columbia 154 I Station l i s t 2\\ -II .Analysis of prosome lengths 37 III Mean Prosome lengths for Large Form along range sampled $8 IV Mean prosome lengths for Small Form along range sampled iiO V Prosome analysis i l l VI Results of T test on headshapes i\.7 VII Analysis of width/length ratios of the urosome segments IL7 VIII Analysis of asymmetry i n f i f t h legs of males, - s t a t i s t i c a l results of the ratio: length right exopod/length l e f t exopod- 5 2 IX A Analysis of the proportionate lengths of exopod segments i n the f i f t h legs of males 5 2 IX B T test on the proportionate lengths of the exopod segments of the l e f t f i f t h swimming legs of males 5 3 >X Width:length values of fi r s t , and/or second segments, l e f t exopod, f i f t h swimming leg, males 5 3 XI A Analysis of proportionate lengths of exopod segments i n f i f t h legs of females 5 9 .AXIBB T test on proportionate lengths of exopod segment 3 o n the f i f t h swimming legs of females 5 9 XII T test on mean lengths of the spinose process on the f i f t h legs of males and females 60 TABLE NO:SUBJECT PAGE XIII Proportions of adults to stage-V copepodites for Indian Arm 76 XIV Proportion of adults:stage-V copepodites Alaskan Cruise of Aug. 1965 77 XV Proportion of adults: stage-V copepodites. Cruises to inlets of Brit i s h Columbia July 1966 and June 1967 78 XVI Proportion of adults:stage-V copepodites. Eastern Pacific cruise of Feb. 66 8l XVII Composition of Breeding Experiments 108 NO. SUBJECT . PAGE 1. A. Diagram of t y p i c a l female Calanus i n l a t e r a l view B. Diagram of t y p i c a l f i f t h swimming l e g o f male Calanus 11 2. Diagram of the process o f headshape measure-ment showing o r i e n t a t i o n o f the cephalothorax 18 3. Map of west coast U.S.A. wit h s t a t i o n p o s i t i o n s 22 li . Map of Indian Arm, B r i t i s h Columbia 28 5. Sub-sampler 31 6. Prosome lengths 35 7. Prosome l e n g t h s : Large Form vs l a t i t u d e 3© 8. Photograph of females I4.3 9. Photograph of stage-V copepodites ijij. 10. Photograph of males ij.5 11. Head shape d i s t r i b u t i o n s lj.6 12. Urosome r a t i o s , d i s t r i b u t i o n ii8 13. Photographs of male f i f t h swimming l e g s 50 Ra t i o l e n g t h r i g h t exopod/length l e f t exopod; f i f t h swimming l e g s o f males %\\. 15. Females: t h i r d exopod seg./prosome segments 16. Females: spinose p r o c e s s , l e n g t h vs frequency 57 17. Males: spinose p r o c e s s , l e n g t h vs frequency 58 18. Map showing d i s t r i b u t i o n of both Large and Small Forms 62 19. T, S diagram of west co a s t data 63 NO. SUBJECT . . PAGE 20. T, S, P diagram of west coast data 64 21. Total animals/m-Vro°nth (both Forms? Indian Arm only) . . 70 22. Yearly cycles: both adults and Stage-V's 71 23. Percentage of adults of each Form over sampling period 72 24. Moulting rate vs temperature - . 84 25. T & S profiles for Indian Arm, Feb., Mar. 1967 87 26. T & S June, profiles for Indian Arm, Apr., May, 1967 88 27. T & S Sep. , profiles for Indian Arm, Ju l . , Aug., 1967 89 28. T & S Dec. , profiles for Indian Arm, Oct., Nov., 1967 90 2 9 . T & S Mar. , profiles for Indian Arm, Jan., Feb., 1968 91 30. Mid-day distribution, Indian Ajem 96 31. 24 hour vert, distributions Feb. 6? & May 67 101 32. 24 hour vert, distributions Jul. 6? & Aug. 6? 102 33. 24 hour vert, distributions Sep. 6? & Jan. 68 103 34. 24 hour vert, distributions Feb. 68 & Mar. 68 104 35. Chlorophyll distribution for Feb. & Mar. 1968 106 I am g r a t e f u l to the o f f i c e r s and men of the CNAV ENDEAVOUR, R / V s VECTOR and EHKOLT. T h e i r help and experience i n p l a n n i n g and conducting the c r u i s e s f o r the f i e l d work i n t h i s study was i n d i s p e n s i b l e , and indeed, without the use of these s h i p s a study of t h i s type c o u l d not be accomplished. I would l i k e to express a s p e c i a l note of thanks to Mr. Murray Storm and to Mr. Heinz Heckel of the I n s t i t u t e of Oceanography, U n i v e r s i t y of B r i t i s h Columbia. Mr. Storm p r o v i d e d i n v a l u a b l e a s s i s t a n c e i n the c o l l e c -t i o n and a n a l y s i s of hydrographic data and Mr. Heckel p r o v i d e d a necessary c a p a b i l i t y i n the c o n s t r u c t i o n , maintenance and r e p a i r o f the sampling gear used d u r i n g the i n v e s t i g a t i o n . During the s o r t i n g and i d e n t i f i c a t i o n phases o f the p l a n k t o n sample a n a l y s e s , Miss Diane Debruyn devoted many hours to t h i s t e d i o u s work, and I s h a l l f o r e v e r be a p p r e c i a t i v e o f her w i l l i n g n e s s to continue and of her i n t e r e s t i n the r e s e a r c h as i t progressed. I express my s i n c e r e a p p r e c i a t i o n to Dr. A l a n G. Lewis and to Dr. B r i a n Bary. Dr. Bary suggested the problem s i n c e i t ap-peared as though i t would be a worthwhile a d j u n c t to a l a r g e r r e s e a r c h problem of h i s own. Dr. Lewis has a c t e d as an immediate s u p e r v i s o r , and to him I am g r a t e f u l of h i s guidance and continued c r i t i c i s m of the r e s e a r c h and f i n a l manuscript. Both Dr. Lewis and Dr. Bary have shown a unique w i l l i n g n e s s to take time out from t h e i r own work and p r o v i d e a s s i s t a n c e as problems arose dur-i n g the course of t h i s i n v e s t i g a t i o n . Finally, I express my gratitude to the remaining staff of the Institute of Oceanography who in one way or another provided their assistance and guidance during the study. A special word of appreciation must go to the Government of Canada for its financial support during the summer months and to the University of British Columbia, Zoology Department for the invaluable teaching assistantships during the winter sessions at the Uni-versity. A knowledge of the ecological relationships between two sympatric species would help in understanding the species prob-lem by elucidating at least some of the mechanisms that act to block the gene flow between two such species populations in the absence of distinct geographical boundaries. Within the calanoid copepod genus Calanus there is a group of closely related species distinguished by a toothed coxopodite on the fifth swimming leg (Brodsky. 1950, 1959. 1965; Jaschnov, 1955. 1957, 1958; Marshall & Orr, 1955). This is a relatively diverse group yet a number of the recognized species overlap geographically, occurring under what appear to be sympatric conditions. Although the various members of this genus are one of the most studied groups of the zooplahkton, mechanisms of speciation within the group and in-terrelationships of the overlapping species have not been satis-factorily resolved. Shan (1962) demonstrated that two "forms" of toothed Calanus sp. occur in southern British Columbia. Bary (personal communi-cation) has suggested that British Columbia might be a region of overlap between these two "forms" with the result that further north or further south one or the other would be absent. Thus, existence of a sympatric condition in the waters of southern British Columbia was implied, but because the taxonomy of the local "forms" was uncertain previously, the experimental approach of this study had to be one that would resolve this taxonomic problem as well as contribute to the understanding of sympatric species relationships. The degree of morphological distinction in the local animals is similar to other well recognized species pairs, e.g., Calanus  finmarchicus and C; helgolandicus (Marshall, personal communi-cation). Under these premises a dichotomy exists whereby re-sults of a more detailed study would show either that the two "forms" are one species but may possibly be diverging sympa-trical ly or that the two "forms" are two distinct but sympatric species. If the former case were true, further study might indicate th£ processes of sympatric speciation within the zoo-plankton. A study where the latter case were true would result in a better understanding of how two planktonic species maintain their integrity under sympatric conditions. With these possibili-ties in mind, the present study was designed so that the.field sampling and experimental results would allow amplification of either possibility. The early reports of toothed Calanus from the west coast of North America relied upon the descriptions of C. finmarchicus from the North Atlantic for identification. There is some simi-lar i|y between the animals from both regions, and as a result the Pacific coast forms were considered morphological variants of C. finmarchicus. Esterly (1905) described the Calanus from the region of San Diego and later (1924) from San Francisco Bay as C. finmarchicus. In his discussion he mentions the differences between C , finmar-chicus and C. helgolandicus but states his agreement with With (1915) that these differences are not significant and that both are C. fInmarchicus. The earliest indication that a species of toothed Calanus may be present in the waters of British Columbia is in a report by McMurrich (19-6). He studied the plankton along the British Columbia coast and mentions encountering large numbers of a copepod "metanauplius" that resembled that of C. finmarchicus. Confirmation of the presence of the species was not possible due to the absence of adults in his samples. . The earliest and most extensive published account on the zoo-plankton from the waters of British Columbia was completed by Campbell (1929). In this publication the toothed Calanus is diagnosed as C. finmarchicus. although a difference between the local males is noted. Following Sars (1903) Campbell notes that some of the males are similar to C. finmarchicus and others to C. helgolandicuB. No differences are noted f o r females and i n the discussion the author states, "the difference between the two forms are so slight that they may both be considered as varieties o i * C. f inmarchicus." The following year (Campbell, 1930) a second paper was published in which the controversy between C. finmar-chicus and C. helgolandicus is discussed. The author s t i l l main-tains the differences in the males but suggests that the two varieties may represent C. finmarchicus and C. helgolandicus thus reversing the earlier conclusion (Campbell, 1930). It is in these two papers, however, that the f irst indication of the ex-istence of two morphologically different forms of Calanus along the west coast appears. Davis (194-9) briefly discusses the problem of correctly diag-nosing the toothed Calanus of the northeast Pacific. The indica-t i o n p resented i s t h a t there i s one s p e c i e s , although i t may be e i t h e r C, f i n m a r c h i c u s or C. h e l g o l a n d i c u s . The f a c t i s mentioned t h a t some c o n s i d e r C. h e l g o l a n d i c u s to be a v a r i e t y o f C. finmarch-i c u s . but any d e f i n i t e statement on the s t a t u s o f Calanus from the n o r t h e a s t P a c i f i c i s not presented because i n s u f f i c i e n t specimens were a v a i l a b l e to permit a d e t a i l e d d i a g n o s i s (Davis, 1949). Brodsky (1948, 1950) mentioned t h a t specimens c o l l e c t e d 1 from the northwestern P a c i f i c were s i m i l a r to those d e s c r i b e d by E s t e r l y (1924) from San F r a n c i s c o Bay. In c o n c l u s i o n he p o i n t s out t h a t E s t e r l y ' s C. fi n m a r c h i c u s i s a c t u a l l y a new s p e c i e s , C. p a c i f i c u s , and on the b a s i s o f mro p h o l o g i c a l d i f f e r e n c e s , par-t i c u l a r l y i n the f i f t h swimming l e g s , separates C. p a c i f i c u s . C. h e l g o l a n d i c u s . and C. f i n m a r c h i c u s . T h i s i s the f i r s t i n d i c a -t i o n t i o n from the l i t e r a t u r e t h a t the west coast toothed Calanus are t a x o n o m i c a l l y d i f f e r e n t from the A t l a n t i c forms. D e s p i t e the comments of Brodsky (1950)» two papers were p u b l i s h e d i n 1957 which d e a l t i n p a r t w i t h the toothed Calanus of the waters o f B r i t i s h Columbia. In the v i c i n i t y of the Queen C h a r l o t t e I s l a n d s specimens o f toothed Calanus were i d e n t i f i e d as' C. f i n m a r c h i c u s and a v a r i a t i o n i n s i z e was noted w i t h the c o n c l u s i o n t h a t these d i f f e r e n t s i z e groups belonged t o d i f f e r e n t broods (Cameron, 1957)* In Georgia S t r a i t a study was c a r r i e d out on the d i s t r i b u t i o n o f zooplankton (Legare, 1957). but there Is no mention o f the occurrence o f two forms o f toothed Calanus. those p r e s e n t being i d e n t i f i e d as C. f i n m a r c h i c u s . The copepods of Ind i a n Arm, B r i t i s h Columbia, were s t u d i e d by Shan (1962). With regard to the toothed Calanus, he noted two size groups but found they were difficult to distinguish. He was the f irst to mention a difference in the shape of the anterior region of the cephalothorax and noticed, as did Campbell (1929), the differences in the fifth legs of the males. In his work, Shan refers to the Large and Small Form of Calanus sp. but in discussion of these two forms calls attention to the similarity of the Large Form to C. glacialis (Jaschnov, 1955) and of the Small Form to C. pacificus (Brodsky, 1950)• According to Shan (1962), however, the local Large Form is much smaller than C.  glacialis as originally described, and the local Small Form dif-fers slightly from C. pacificus (Brodsky) in the structure of the fifth swimming legs. The toothed Calanus of Indian Arm is further distinguished from C. finmarchicus by the shape of the row of teeth on the fifth swimming legs and from C. helgolandicus by the shape of the anterior portion of the cephalothorax (Brod-sky, 1950). This work is the f irst to suggest the possibility that C. glacialis may be represented in the zooplankton of the coast of British Columbia, and i t substantiates the speculation by Campbell (1929) that two forms in fact occur. In his final remarks, Shan suggests that a study in greater detail is needed to clarify the systematic position of the two forms. Since the appearance of Brodsky's work on the Calanoida (Brodsky, 1950), the species Calanus pacificus appears to be ac-cepted by a greater number of investigators. LeBrasseur (1964) published a checklist of zooplankton species for the waters of British Columbia and in this account he refers to the C. finmar-chicus type as C. pacificus. Fleminger (1964) described the toothed Calanus from California coastal waters as C. helgolandi-cus but does indicate the possibility that this animal may actu-ally be C. pacificus* Both of these publications cover a large amount of material so that a detailed study of the systematic position of any one species was not attempted and the acceptance of Brodsky's C. pacificus appears to be a matter of convenience. Groups of specimens of Calanus pacificus collected in vari-ous parts of the Pacific are diverse enough morphologically that they can be distinguished. Thus Brodsky (1965) sub-divided the group into a number of sub-species and erected C. p. C a l i f o r n i a -us for the sub-species from California waters. Brodsky shows i t to be distributed from Cape Flattery, Washington, to Baja Cal-ifornia. In addition to the speculation by Shan (1962) on the occur-rence of C. glacialis in British Columbia, Brodsky (1965) sug- . gests that the species may occur as far south as Cape Flattery, Washington, but a lack of material prevents the formulation of an accurate distribution for this species. Subsequent papers dealing with the toothed Calanus in British Columbia fa i l to mention C. glacialis or even that two forms appear in the zoo-plankton with the result that C. pacificus (helgolandicus) is the only species recognized (Fulton, 196b} Mullin, 196b). Since there is l i t t l e doubt of the existence of two morpho-logically distinct groups of toothed Calanus in British Columbia (Shan, 1962; Bary, personal, communication), i t is evident from the literature that their taxonomic position is in need of clari-fication. The Intent is to substantially demonstrate the taxon-omic position on both morphological and ecological grounds. The ecological relationships of two forms in an area of overlap pro-vide a valuable set of criteria in determining whether two such forms are behaving as true species populations in the sense of Mayr (1942). In the case of the toothed Calanus there has been very l i t t l e done in terms of viewing the taxonomic status of the morphological variants through their ecology. This study deals only with the adult males and females and the juvenile Stage-V copepodites of the forms mentioned by Shan (1962). Other stages, i . e . , f irst through sixth naupliar and first through fourth copepodite exhibit no distinguishing mor-phological characters on which they may be separated. For the reader who may be unfamiliar with the biology of toothed Calanus spp., a brief account of the broader aspects is included here. Comprehensive accounts may be found in a number of books devoted to the subject (Caiman, 1909J Marshall and Orr, 1955; and Waterman, i 9 6 0 ) . The animals are dioecious, holoplanktonic, neritic members of the zooplankton occurring in the upper 500 meters of the water column. They are generally found in the temperate, sub-polar and polar waters. A few have been reported from tropical or sub-tropical regions (Wilson, 1942 & 1950; Marshall and Orr, 1955)* Fertilization occurs by means of sperm from spermatophore produced by the male and attached to the female. Sperm cells are non-motile and are generally stored in the paired spermathecal sacs of the female genital segment or f irst urosomal segment (Fig. 7 ) . Eggs are shed by the female and are fertilized internal to the g e n i t a l pore where the l e f t and r i g h t c a n a l s of the spermathecal sacs j o i n the d i s t a l end of the o v i d u c t (Heb-erer, 1932). Once r e l e a s e d the f e r t i l i z e d eggs develop a p a r t from the female, and normally h a t c h i n g occurs a f t e r twenty-four hours i n a t l e a s t one s p e c i e s ( M a r s h a l l and Orr, 1955)• Subsequent to hatc h i n g the young moult through s i x s u c c e s s i v e n a u p l i a r stages, between the s i x t h n a u p l i u s and f i r s t copepodite stage, a marked change i n morphology i s e v i d e n t , and the j u v e n i l e assumes an appearance l i k e t h a t o f the a d u l t . As the animals moult from copepodite Stage-I to Stage-V, the young become l a r g e r and a d d i -t i o n a l segments are s u c c e s s i v e l y apparent. The f i n a l moult r e -s u l t s i n the a d u l t , and secondary s e x u a l c h a r a c t e r i s t i c s become e v i d e n t . Some r e f e r to the a d u l t as Stage VI ( M a r s h a l l and Orr, 1955). The Stage-V copepodite has been r e f e r r e d to as the overwin-t e r i n g stage. (Raymont, 1963s M a r s h a l l and Orr, 1955)' T h i s par-t i c u l a r stage i s unique because i t can with s t a n d environmental extremes t h a t n o r m a l l y a f f e c t the s u r v i v a l of the other stages. I t i s i n t e r e s t i n g to note t h a t development to the f i f t h copepodite stage takes approximately one month f o r Calanus f i n m a r c h i c u s (Mar-s h a l l and Orr, 1955), and a s i m i l a r time span i s i n d i c a t e d from the r e s u l t s of t h i s study f o r the e a s t e r n P a c i f i c s p e c i e s . How-ever, the l e n g t h of time spent i n the Stage-V alone can be a mat-t e r of months. In one i n s t a n c e d u r i n g t h i s i n v e s t i g a t i o n , a 4-l i t e r beaker c o n t a i n i n g 10 to 15 Stage-V copepodites was l e f t i n the dark on a s h e l f i n a cold-room (5«5°C) without food o r water change f o r b months. A t the end of t h i s time they were moving f r e e l y and responded to a g i t a t i o n of the water. The following frequently used terms are defined in order to clarify their use in the text and to avoid confusion with slight-ly different meanings attached to them by other authors. Cephalothoraxi the anteriormost portion of the prosome of calanoid copepods consisting of the head and first thoracic somite (Marshall and Orr, 1955) (Fig. 1). 1 Neritic waters: those waters which are considered as "coastal" and which cover the continental shelf. They are often rich in nutrients and are generally regions of high biological productivity. Oceanic waters: those waters that are seaward of neritic waters and in which the depth to the bottom is greater than 100 fathoms. Prosome: the larger portion of the body of calanoid copepods consisting of the cephalothorax, which forms the anterior part, and five or six free thoracic somites forming the posterior part (Fig. 1). The term is synonomous with metasome as used by Marshall and Orr (1955). Species: a group of organisms which interbreed and maintain populations that are reproductively isolated, under natural con-ditions, from populations of other similar and closely related organisms (Mayr, 19^2). Standard hydrographic depths, as used in this study they are, 0 , 5 , 10 , 2 0 , 30, 50, 7 5 . 100, 125, 150, 175. and 200 meters. In the few cases where bottle casts were deeper than 200 meters, bottles were spaced 100 meters apart. Toothed Calanus; That group of species within the genus Calanus bearing a dentate inner border on the coxopodite of the fifth swimming legs (Fig. 1 ) . Urosome: The smaller portion of the body of calanoid copepods, consisting of the last one or two thoracic somites and the abdomen, with a maximum of four segments including the telsoni and with a pair of caudal rami )Caiman, 1909. Marshall and Orr, 1955) (Fig. 1 ) . Water body: a group of related points on a temperature-salinity diagram which indicate a body of water distinctrfrom water surrounding i t either in the veritcal or horizontal direc tion (Bary, 1963) . Figure 1. A diagram of female Calanus i n l a t e r a l view; Pr., prosome} Ur.i urosome; Cephthx., cephalothoraxj R.F. , r o s t r a l filament; G.S., g e n i t a l segment; C.F., caudal furca. B, diagram of f i f t h swimming leg of male Calanusi Ex., exopodite; End., endopoditej Sp.P, , spinose process; Bs., basipodite; Cx., coxopodite; Th,, teeth. The scope of the study has made i t necessary to apply a num-ber of d i f f e r e n t techniques. For thi s reason the materials and methods are c l a s s i f i e d according to the section of the study i n which they were employed, with the exception of the opening sec-t i o n on sampling techniques. I n t r i n s i c problems encountered i n some of the procedures are also discussed. General Sampling Procedure A routine procedure was followed on the cruises. Tempera-ture and s a l i n i t y measurements were taken over the portion of 1 the water column to be sampled b i o l o g i c a l l y . On early cruises oxygen measurements were taken, but there appeared to be no cor-r e l a t i o n between the oxygen concentrations encountered and the v e r t i c a l d i s t r i b u t i o n of Calanus and oxygen measurements were discontinued. Standard hydrographic depths were used, and the horizontal plankton sampling was planned so that the nets would sample about these same depths. • ' Atlas bottles and closed reversing thermometers were used for hydrographic sampling. A bathythermograph was employed to check against readings obtained from the reversing thermometers, and to aid i n int e r p o l a t i o n of hydrographic conditions betweem sampling depths. S a l i n i t y samples were drawn from the Atlas bottles and run at a l a t e r time on an inductively coupled s a l i n -ometer manufactured by Auto-lab Industries Pty. Ltd., Sydney, A u s t r a l i a . Meterological observations were made at each st a t i o n . When 24 hour stations were run at station number 9 in Indian Arm, only one hydrographic station was made during the period. A 70 centimeter ring net with a mesh aperture of 270 microns square was used for vertical sampling. This mesh was chosen for its relative effectiveness in retaining plankton of the size of Calanus. The net is cylindrical for 2/3 of its length. The distal 1/3 is a cone which xtapers to a diameter of 15 centimeters at the cod end. The design is considered particularly efficient for vertical sampling (E. Gl l f i l l an , personal communication). Prior to the design and construction of this 70 centimeter ring net, available equipment included a Discovery net with a mesh aperture of 300 microns square, and a 1 meter ring net of mesh aperture ?00 microns square. These two nets were used in some of the early preliminary vertical sampling in collecting speci-mens for morphological study. 1 Clarke-Bumpus nets with a diameter of 13 centimeters and mesh aperture of 366 microns square (#2 nets) were used for strat-ified tows. A bathykymograph, time-depth recorder, was used in conjunction with-these nets to monitor a particular tow. The? specific procedure used for determining the depth of the Clarke-Bumpus nets is described in Appendix I I . Life specimens were collected with the 70 centimeter net and thermos jugs were used to transport living material to the lab-oratory. Water for maintaining these specimens was-; collected with a 16 l i ter Van Dorn water bottle, filtered with a 0.45 micron Millipore, and stored in 20 l i t er Nalgene carboys at 5»5°C in the laboratory cold room. Animals were c o l l e c t e d from I n d i a n Arm s t a t i o n 9 ( F i g . (ty) and G e o r g i a S t r a i t S t a t i o n I (^9°17'06" N, 12 3°50 ,00" W). The s p e c i -mens were pr e s e r v e d with. 5% f o r m a l i n b u f f e r e d w i t h sodium borate u n t i l they c o u l d be s o r t e d and p l a c e d i n 1 dram v i a l s . Specimens" were s t a i n e d and c l e a r e d i n one step i n C l o r a z o l Black E d i s s o l v e d i n a $0% l a c t i c a c i d s o l u t i o n . A f t e r r e t e n -t i o n i n t h i s p r e p a r a t i o n f o r a minimum of 24 hours animals were t r a n s f e r r e d to a 50% g l y c e r i n s o l u t i o n f o r s h o r t term storage u n t i l they could be d i s s e c t e d and mounted on m i c r o s l i d e s . Appendages were d i s s e c t e d u s i n g Minuten-Naden and mounted i n CMC-S d i l u t e d about 2:1 with CMC-10. These two water s o l -uble media are manufactured by TURTOX and are convenient f o r mounts of t h i s n a t u r e . O r a l appendages were mounted on 22 by 40 mm cover s l i p s which were mounted i n t u r n on cardboard s l i d e s so specimens could be s t u d i e d from e i t h e r s i d e under h i g h power o b j e c t i v e s . Peraepods were mounted on r e g u l a r g l a s s m i c r o s l i d e s . A f t e r d i s s e c t i o n of the appendages, whole mounts of the remaining pro-some and urosome were made by g l u i n g 1 cm, diameter p l a s t i c r i n g s to a g l a s s s l i d e , and then m e l t i n g g l y c e r i n j e l l y i n the r e s u l t -i n g c a v i t y . U s i n g t h i s technique, the whole mounts can be removed a t a l a t e r date by h e a t i n g the s l i d e g e n t l y , removing the cover s l i p and p l a c i n g the specimen i n g l y c e r i n . G l y c e r i n j e l l y was chosen as a mounting medium f o r whole mounts because i t does not shrink as is the case for CMC-S and CMC-10. The two latter media wi l l dry out with thick mounts and thus damage the specimen. A l l measurements were made with a pre-calibrated, optical . • micrometer mounted i n a Zeiss compound microscope. Measurements of the prosome and urosome were made before dissection of the ap-pendages by placing each specimen in a hanging drop of glycerin. This technique avoids the problem of squashing or distortion by a cover glass and by dissection. Every animal was assigned a serial number so that subsequent measurements of the mounted ap-pendages could be maintained with the prosome and urosome measure-ments of the same specimen. i Among the morphological differences found in species and sub-species of Calanus. head shape is a consistent feature used to separate one type from the other• In their comparisons of the species many workers usually bring this feature into their descriptions (Brodsky, 1 9 5 0 ; Marshall and Orr, 1 9 5 5 ; Sars, 1 9 0 3 ; Jaschnov, 1 9 5 5 ) » but rarely has i t been described quantitatively. Often the slight differences in headshape are difficult to show on a drawing (Bary, personal communication).. For this reason an attempt was made to arrive at a means of measuring this feature in the llocal> animals so that the numerical quantities could be subjected'to statistical analysis and the significance of the headshape differences demonstrated. Several methods of headshape measurement were tried includ-ing one used previously on Calanus finmarchicus and C. helgoland-icus (Barnes and Barnes, 1 9 5 3 ) . A l l methods involved the,analysis of the curve of the cephalothorax. The reference points used, so that tracings were uniform, were the articulation surfaces of the cephalothorax including those at the bases of the oral appendages. A vector analysis, measurement of head angle, and a curvilinear regression were tried in addition to the method described by Barnes and Barnes (1953)* The vector analysis failed to show any difference in headshape although It was obvious from the ap-pearance of specimens used that a difference in curvature of the anterior cephalothorax did exist. The method of measuring head angle was unsuccessful in distinguishing the headshapes of the males, but the curvilinear regression was successful in demon-strating a difference between the adults of both sexes and juven-ile &tage-V copepodites when headshape differences were apparent from direct observation. The method using a curvilinear regression analysis involved tracing the animal in lateral aspect. Since the posterior artic-ulation of the cephalothorax has a slight thickening in the mid-dorsal l ine, i t is an easy point to find in a photograph of the animal and was consequently chosen as a reference point. The second reference point was the posterior surface of the base of the rostral filament. Animals chosen for analysis were photo-graphed in lateral view. The negatives were projected onto graph patper wdth 1mm divisions by means of a photographic enlarger. Magnifications were kept consistent by projecting a scale onto the graph paper and setting the enlarger so that one division on the projected scale always covered the same number of divisions oh the graph paper (Fig. 2). X and Y axes were chosen so that the Y axis ran between the two reference points (Fig. l ) . The point at the base of the rostral filament.on the posterior surface was placed so that i t would l ie on the intersection of two axes on the graph paper, and the origin of the X and Y axes was always set 1 cm below this point since the head outline extended slightly anterior. ! Thus, the base of the rostral filament at the posterior surface always had the coordinates X _ 0 and Y = 10. Once the reference points were aligned on the graph paper, the outline of the lateral view of the cephalothorax was traced from the anterior surface of the base of the rostral filament to the posterior articulation. Values of X and corresponding values of Y were then read from the graph until a maximum value of X was reached. Consequently only the anterior portion of the cephalothorax was analysed, and i t is this portion that appears different. The X, Y values were then subjected to a regression analysis where A regression coefficient was calculated for each animal. Length measurements of the animals were made by placing specimens on their sides and measuring the length of the prosome fr'om the anterior end of the cephalothorax to the posterior end of the last prosome segment. Individual length and width measure-ments of each segment were also recorded. The length and width of each segment of the urosome was recorded. For the caudal rami, the width was measured at the articulation with the last urosomal segment. The length was measured from this anterior articulation to the insertion of the posteriormost seta. Figure 2. Diagram of the process of headshape measurement showing the orientation of the cephalothorax. The appendages of the cephalothorax are much alike in the local species and are morphologically similar to other species in the genus. The length and width of each antennule segment was determined; for the antennae, the length and width of the second segment of the exopodites was measured. Measurements were taken of those swimming leg segments that appeared proportionately different. Width measurements were made when i t was felt width to length ratios of a particular segment might show a proportionate difference between specimens. Lengths of exopodite segments were measured from the proximal articulation surface to the distal articulation surface. Total length of the exopodites was determined by summing the individual length measurements df each segment. Teeth on each coxopodite were counted. Male specimens of Calanus show the greatest amount of vari-ability in the lengths of the left and right exopods, and the degree of asymmetry is a common taxonomic character (Brodsky, 1965? Jaschnov, 1955) . For females, the legs are symmetrical, but the first segment of the exopodite has been reported to vary in proportion between C. finmarchicus and C. helgolandicus (Jaschnov, 1955). The degree of asymmetry in the local species was measured by dividing the length of the right exopodite by that of the left . Length measurements of individual exopod seg-ments were proportionately different in length. It was felt that proportionate differences could be elucidated by using a measure-ment common in proportion to most species of Calanus. This measurement would serve as a common denominator in any ratios - 2 0 - v 1 formed, and make i t possible to d i r e c t l y compare features which vary i n degree among the toothed species of Calanus. Based on his work of Calanus species around the world, Bary (personal communication) has suggested that the proportionate-lengths of the fourth and f i f t h prosome segments (cephalothorax considered the f i r s t ) show very l i t t l e v a r i a t i o n (Figs. 1 and' 8^10). This was tested on the l o c a l species by forming r a t i o s with the prosome segments. The length of any one prosome segment was placed i n the numerator and the sum of the lengths of prosome segments one through f i v e was placed i n the denominator. The l a s t or s i x t h prosome segment was deleted because i t s length i s hard to measure accurately and would therefore introduce a samp-l i n g error i n the analysis. The proportionate lengths of the' fourth and f i f t h prosome segments were found to be i d e n t i c a l i n the l o c a l species and were chosen as the common measurement for forming r a t i o s with the exopod segments of the f i f t h legs. The length of each exopod segment was divided by the sum of the ; lengths of prosome segments four and f i v e for each animal. Measurements were analyzed to determine any s i g n i f i c a n t d i f -ferences. Student's " t " tests were used to determine the s i g n i -ficance of differences i n the means of measurements between the two^forms described by Shan (1962), and variances were tested by the F test. Regression analyses were used to determine the dependence or independence of the differences found and prosome length. A P value of 0.01 was used i n a l l tests. A complete set of drawings to i l l u s t r a t e the appendages arid the body shapes was made with a camera l u c i d a . These are included i n AppendixII, with the mo r p h o l o g i c a l d e s c r i p t i o n of the l o c a l animals. D i s t r i b u t i o n a l Survey Between I965 and 196? s e v e r a l l o n g c r u i s e s were completed c o v e r i n g a range from 3 3 0 n o r t h to 59° n o r t h along the west coast of North America ( F i g . 3 ) . In the waters n o r t h o f Vancouver, B r i t i s h Columbia, sampling was c a r r i e d out i n Georgia S t r a i t , Bute I n l e t , K n i g h t I n l e t , Johnston S t r a i t , and Queen C h a r l o t t e S t r a i t . In the l a t e summer of I965 a c r u i s e on CNAV ENDEAVOUR through the I n s i d e Passage of A l a s k a p r o v i d e d the o p p o r t u n i t y to sample many of the i n l e t s o f so u t h e a s t e r n A l a s k a i n c l u d i n g G l a c i e r Bay, a c o l d i n l e t l o c a t e d a t the northernmost p a r t of the A l a s k a n a r c h i -pelago. The c r u i s e i n c l u d e d s t a t i o n s i n the North e a s t P a c i f i c , a l o n g the o u t e r c o a s t of A l a s k a , and i n Dixon Entrance and Queen C h a r l o t t e Sound. South of Vancouver, a s i n g l e c r u i s e i n e a r l y 1966 on CNAV ENDEAVOUR was arranged to example the region"from the mouth of Juan de Fuca S t r a i t to San Diego, C a l i f o r n i a . The c r u i s e was s e t so t h a t the edge of the c o n t i n e n t a l s h e l f (100 fathom l i n e ) was c r i s s - c r o s s e d i n l e g s of approximately 100 m i l e s i n l e n g t h . T h i s p r o v i d e d the o p p o r t u n i t y to sample over the c o n t i -n e n t a l s h e l f , the c o n t i n e n t a l s l o p e , and deep oceanic water. S t a -t i o n s were a l s o s e t over deep r e g i o n s such as the Monterey Canyon and the Mendocino Escarpment. Si n c e the c r u i s e s t o A l a s k a and San Diego ran c o n t i n u o u s l y over a 24 hour day, samples along the range were taken a t a v a r i -e t y o f d i f f e r e n t times, and i t was p o s s i b l e to o b t a i n some idea of the effect of hydrographic conditions on the vertical migra-tions of the toothed species of .Calanus* Samples taken on cruises to the inlets of southern British Columbia were generally during daylight hours, but the study in Indian Arm included 24-hour sampling of one station in order to study the vertical migration patterns in detail. Table I is a l i s t of oceanographic stations occupied in this study. For ease in description place names are used in the text while the exact geographical coordinates of the sta-tions may be determined from this Table. Station numbers or letters in parentheses are the official designation for the sta-tion as given in the data reports of the Institute of Oceano-graphy at the University of British Columbia. Stations from which samples were drawn for the morphological, distributional and ecological analyses are indicated by an asterisk in the ap-propriate columns. . Ecological Study The program was designed to provide data about the forms of toothed Calanus described by Shan (1962) which would help in answering the following questions: 1. Do both forms occur in one stage or another throughout the year? 2. Are the yearly cycles, particularly the time of breed-ing and spawning, the same for both? 3. Is the time of reproduction the same in other areas? TABLE I STATION LIST M=Morphology study; D=Distributional study; E=Ecology study. STATION LATITUDE LONGITUDE N D E Gla. Bay 8 58 41.2N 136 11. OW * tt Icy St. 3 58 14.7 135 24.3 * * « Lynn Canal 10 58 40.3 135 06.9 * Icy St. 1 58 18.0 136 19.2 tt » Behm East 18 54 42.0 131 10.0 tt Clarence 22 54 42,5 131 44.6 » Behm East 11 55 15.1 131 02.7 # Behm East 2 55 59.0 131 16.0 » Behm West 7 55 39.2 131 45.4 « Clarence 14 55 26.5 131 58.5 • Clarence 6 56 01.6 132 45.0 tt Sumner 10 56 0 3 . 0 133 48.7 « « Lynn Canal 40 56 17.5 134 26.5 Lynn Canal 30 57 02.8 134 41.8 # Lynn Canal 20 57 49.8 134 51.7 Pacific A 57 48.0 137 05.0 » « Pacific B 56 04.0 135 29.5 * tt # Pacific C 55 28.0 134 58.0 # « « Pacific D 54 30.0 134 02.0 * Pacific E 54 28.0 132 25.0 « Pacific F 51 10.0 129 50.0 « « Pacific G 51 04.9 128 12.0 * STATION LATITUDE LONGITUDE N D E Johnston St 3. 50 30.ON 126 2 0 . 9W * # Queen Char. St. 50 45.5 127 20.0 Knight I n l e t 3 5° 39.7 126 05.1 # * •H-S u t i l Chan. 1 50 05.0 125 07.0 * * P a c i f i c 1 48 '25.0 124 50.0 * P a c i f i c 2 48 00.0 126 08.0 * * P a c i f i c 3 47 38.2 . 125 37.0 * P a c i f i c 47 13 .0 124 53.0 * * P a c i f i c 5 47 00.0 124 30.0 * P a c i f i c 6 46 35.0 124 34.5 P a c i f i c 7 45 20.0 124 50.0 * * • P a c i f i c 8 44 41 .5 124 34.0 P a c i f i c 9 43 45.0 124 20.0 # P a c i f i c 10 43 25.0 124 37.5 * P a c i f i c 14 40 59.5 124 2 0 . 5 * P a c i f i c 15 40 2 7 . 0 124 36.5 * P a c i f i c 16 40 10.0 124 55.0 * P a c i f i c 17 39 2 9 . 0 124 27.0 * P a c i f i c 18 38 45.2 123 45.0 « P a c i f i c 19 38 15.3 123 10.0 P a c i f i c 20 37 48.0 122 31.0 * P a c i f i c 21 37 51.0 122 26.0 * P a c i f i c 22 37 00.0 122 20.0 P a c i f i c 23 36 42.0 122 06.0 # » * P a c i f i c 24 36 17.0 122 03.0 •a * Pacific 25 34 45. ON 120 50. OW * Pacific 26 34 2 5 . 0 120 15.0 « Pacific 27 33 , 55.0 119 50.0 « Pacific 28 33 35.5 119 11.0 * Pacific 29 33 09.5 118 2 0 . 0 » Pacific 30 32 4 5 . 0 117 31.0 * * * Pacific 33 37 47 .5 123 15.0 # Pacific 34 40 2 0 . 0 124 27.0 •* * Pacific 35 42 2 5 . 0 124 45.0 * Pacific 36 42 50.0 124 4 5 . 5 *• « Pacific 39 46 15.0 124 33.0 » Unimak Pass 54 00.0 165 0 0 . 0 * * Georgia St. 1 49 15.0 123 41.0 # Saanich In. 48 38.0 123 30.2 * * Malaspina St. 49 34.0 124 0 9 . 0 * Bute In. 50 24.0 125 04.7 Juan de Fuca 7 48 19.0 124 11.9 « Georgia St 2 49 51.0 124 50.0 * correlation between vertical distribution and the pre-vailing hydrographic conditions? 5. What happens to the spatial relationship of the popula-tions in the vertical direction over a 24 hour period? 6. Are the two forms reproductively isolated and therefore good species as defined by Mayr (1942)? 7. Is there any association between one form or the other to particular water bodies in the sense applied by Bary (1963)? Indian Arm, an inlet near Vancouver, British Columbia, was chosen for the ecological study (Fig, 4). Relative abundance of both species over the year, physiography of the inlet, and the proximity of Indian.Arm to Vancouver were the main reasons for choosing this area. Preliminary sampling indicated that both populations of toothed Calanus were breeding populations, and that their abundance during the year did not appear to be affected by the large blooms of a related non-toothed species, C. plumchrus. that occur in the Strait of Georgia and other in-lets in the region. The inlet is a relatively deep basin with a maximum depth of 245 meters and a shallow s i l l depth of approxim-ately 30 meters (Q'ilmartin, 1962). The mouth of the inlet is comparatively narrow and adjoins Vancouver harbor which is sep-arated from the Strait of Georgia by a second narrow entrance, wFJiis.tsNacfeQwg,M On the basis of these boundary conditions, i t was felt that immigration and emigration on the part of Calanus might be restricted, and any continuing research program could reason-Figure 4 . Map of Indian Arm, B r i t i s h Columbia, showing location of s t a t i o n number 9 » STN. 9 ably assume that the same populations were being sampled on each cruise. The proximity of Indian Arm to Vancouver became important when collecting live animals and transporting them to the laborat-ory for further work. By keeping the amount of time the animals are kept in collecting containers to a minimum, there is a lower risk of exposing the specimens to conditions which may be damag-ing and deterrant to survival. A station was selected over the deepest part of Indian Arm for this work, station 9 of Figure 4. Vertical hauls were taken monthly from October 1966 to April 1968. These included the whole water column from approximately 200 meters to the surface. Additional hauls at any one sampling period provided live animals for laboratory experiments. From February I967 to March 1968, a monthly series of stratified tows was taken at noon, 1200 hours, With the nets sampling at eight different depths to include the major portion of the water column. Twenty-four hour stations were run in February, May, July, Augusts and September of I 9 6 7 , and in January, February, and March of 1968. The pattern of sampling was the same as for the mid-day stations, except that samples were taken every six hours. Preserved samples were placed in plastic petri dishes with an engraved grid forming 1 cm squares. This grid facilitated counting by enabling the sorter to keep track of the counted and uncounted portions of the dish. The numbers of males, females and stage-V copepodites of both forms were recorded, and in the later samples the numbers of females with attached spermatophores were also counted. Samples taken with the Clarke-Bumpus nets were not sub- ; sampled prior to counting, but samples obtained from vertical' hauls were split into four equal portions with the aid of a cylindrical sub-sampler (Fig. 5 ) . During the sub-sampling pro-cedure, the entire plankton sample was poured into the cylinder without the partition. After thoroughly stirring the sample, the partition was immediately placed in the tube. Subsequently any number of the chambers could be emptied into an appropriate container and the sample counted,. In order to check the ef f ic i-ency of this sampler, several entire plankton samples were count-ed by counting a l l the specimens in each chamber, then by summing the counts for the four chambers and dividing by four an ex-pected number of animals per chamber was derived. Applying a chi-square test the effectiveness of the sub-sampler in dividing the original sample into four equal parts was determined. For toothed Calanus, the instrument consistently gave acceptable 're-sults when there were at least six specimens per chamber, but for larger organisms such as etuphausiids, the discrepancy in counts between the four chambers was too large to be acceptable and the trapping of individual specimens under the partitions was a problem. ' For an estimate of the relative amount of food available at various depths, analyses of chlorophyll A were run in February and March of 1968 by the method of Strickland and Parsons (1965). Since chlorophyll A is common to a l l phytoplankton i t was felt unnecessary to determine the amounts of the other chlorophylls. The turbidity of the surface water was also used as an indication o f the degree of primary p r o d u c t i v i t y d u r i n g these two months. Water samples were obtained from standard hydrographic depths with A t l a s b o t t l e s . In March 1968, n e t s with a mesh a p e r t u r e o f ?6 microns square were att a c h e d to Clarke-Bumpus frames, and an a d d i -t i o n a l s e r i e s of tows a t a l l e i g h t depths was completed. In a d d i -t i o n to those taken f o r c h l o r o p h y l l a n a l y s i s , samples were a l s o taken from the A t l a s b o t t l e s and preserved i n L u g o l s o l u t i o n f o r l a t e r i d e n t i f i c a t i o n and e s t i m a t i o n o f the d i s t r i b u t i o n of phyto-p l a n k t o n over the 200 meter* water column. Specimens o f Calanus captured i n the f i n e mesh n e t s were su b j e c t e d to gut content a n a l -y s i s to determine the types o f food organisms i n g e s t e d . For the moulting and breeding experiments, Stage-V copepodites of each form d e s c r i b e d by Shan (1962) were p l a c e d i n p l a s t i c boxes. These boxes were d i v i d e d i n t o 24 compartments each with a 100 ml c a p a c i t y , and one specimen was p l a c e d i n each compartment. An e x t r a stock was kept a f t e r each c o l l e c t i n g c r u i s e i n the event of failure:.;:, or mishap i n the experimental boxes. Specimens -were kept i n ' 4 l i t e r beakers with 25 to 30 animals per beaker. The compartmented boxes were p l a c e d i n d i f f e r e n t temperatures as the p a r t i c u l a r experiment d i c t a t e d . Temperatures o f 5 , 10 and 15°C were used. W i t h i n each temperature there were two boxes a t any one time. One wasua c o n t r o l with no food organisms the o t h e r an experimental box with food organisms. To provide a second con-t r o l , an experiment a t 5°C was always run s i m u l t a n e o u s l y with an experiment a t one o f the other temperatures. The phytoplankton food source c o n s i s t e d o f D u n a l i e l l a st>. and phaeodactylon t r i c o m u t u m . Boxes were checked every two or three days, and the number of specimens which had moulted to the adult stage was recorded. After moulting, adults were placed in 4 l i t e r beakers for breed-ing experiments by the following scheme: Large Form males x Large Form females Small Form males x Small Form females Large Form males x Small Form females Large Form females x Small Form males The breeding experiments were conducted at 5° and 10° C. Fertilization was confirmed by dissecting out the spermathecal sacs of females and squashing them in aceto-orcein nuclear stain. Morphology Detailed descriptions of the toothed Calanus sp. forms noted by Shan (1962) are included as an appendix. Morphological differ ences between the two are presented in this section. Table I shows the stations along the west coast of North America where sub-samples of animals were taken for use in the morphology study Prosome Two size groups of toothed Calanus are evident.although overlaps in length distribution occur, particularly in adults (Fig. 6 ) . Wales are generally smaller than females. On the basis of prosome length measurements of 50 animals of each sex the mean length values were determined and are presented in Table II with the results of the T test on the data. A change %n the average length of Shan's Large Form (1962) was noted whil§ sorting specimens from different regions of the west coast. Measurements of prosome length reflect this change, resulting in a decreased length toward" the southern extent of the range. The results are summarized in Table III. Figure % presents the change in prosome length for the Large Form, and length values reported by Park (1968) and by Jaschnov (1955) are included for'comparison. A regression analysis indi-cated a significant change of prosome length on latitude based, on the animals measured, in this study. The calculated regression Figure 6. Prosome lengths. 20-15-10-5-Large Form (males) 1S 10-5-Small Form (males) o 15-| 10--5 5-c Large Form (females) ^ 15-1 I 10-E 5-Small Form (females) 15-10-5-Large Form (stage-V) 15-10-5-Small Form (stage-V) • 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1.8 2.0 2.2 2.4 2.6 2.8 3.0 3.2 Prosome length (mm) Pigure 7 . Prosome lengths: Large Form vs. latitude; open circlest one animalj closed circles: two animals; open t r i -angles: three animals; closed trianglesi four or five ani-mals; for females, A-F: data from Park (1968) along meridi-an 154° W. longitude, Gi data from Jaschnov (1958) from sea of Okhotsk; for males, A-C from Park (1968), Di Jaschnov (1958); for stage-V copepodites, A: data from Jaschnov (1958). ANALYSIS OF PROSOME LENGTHS FORM. SEX MEAN VARIANCE CALC. T T(.Ol) Large Small females females 2.9 2.4 0.027 0.024 16.62 2.63 Large Small males males 2.8 2.2 0.010 0.013 29.47 2.62 Large Small Stage-V Stage-V 2.6 2.1 0.022 0.016 14.55 2.66 *MEAN PROSOME LENGTHS FOR LARGE FORM ALONG RANGE SAMPLED STATION FEMALES MALES C-V Unimak Pass 3.1 mm — W W W Glacier Bay 3.2 3.1 mm 2.9 mm Icy Strait 2 . 9 2 .9 2 . 8 Lynn Canal 3.1 2 .7 2 .9 Pacifici Stn B 3.1 2.6 2 .8 Pacific: Stn C — 2.6 Queen Charlotte Sound 3 . 0 2 . 8 2 .7 Queen Charlotte Strait 2 . 8 2.7 2.7 Knight Inlet 3 . 2 2 . 8 2 . 8 S u t l l Channel 2 . 8 2 . 8 2 .8 Indian Arm 2 . 9 2 .8 2 .6 Pacific: Stn 1 2.6 2.6 — Pacific: Stn 2 2 .7 2 .7 2 .5 Pacific: Stn 7 2 .7 2 ,7 2.6 Pacific: Stn 10 2.7 — 2 . 4 Pacific: Stn 36 2.6 — — — Pacific; Stn 34 2.7 2.7 — — — * Sample size for each class was 5 except for Indian Arm, where 10 of each sex and 10 stage-V copopodites were measured. line is on each graph, and the range of prosome lengths for each station may be determined from this diagram. In the case of Indian Arm, a random sample of 10 males, females, and Stage-V copepodites was drawn for the purpose of comparison to other areas. Similar measurements on Shan's Small Form, collected from a series of stations along the west coast (Table I and Table IV), do not ex-hibit the same variation in prosome length with latitude, although the Stage-V copepodites are somewhat smaller at the southernmost portion of the range sampled in this survey. Table IV summarizes the data for this form. The results of the analysis for possible variation in the proportionate lengths of the prosome segments are presented, in Table V. The variation between the two forms is slight and sta-t i s t ical ly insignificant. The ratio, segment 1/sum of segments 1 to 5» nas the greatest variation within and between forms, and may reflect the variation in head shape evident between the two forms. The ratios formed from segments 3, 4, and 5 are the most consistent. A similar analysis of specimens from the various sta-tions along the range of each form showed no significant change in proportions. Head Shape The shape of the anterior end of the cephalothorax in lateral view differs between the two local forms of toothed Calanus. The Stage-V copepodites appear much like the adult females making i t possible to distinguish the head shapes of the two forms at this stage. Large Form females and Stage-Vs have a rounded head, in - R O -* M E A N P R O S O M E L E N G T H S ' . F O R S M A L L F O R M A L O N G R A N G E S A M P L E D STATION FEMALES MALES C-V S u t i l Channel 2 . 5 ma 2.3 mm 2.2 mm Indian Arm 2 . 4 2.2 2.1 Pacifies Stn 7 2 .5 2.3 Pacific: Stn 10 2.2 2.0 1.9 Pacific: Stn 36 2 .2 . 2 .0 1.9 Pacific: Stn 34 2 . 4 2.1 1.9 Pacific: Stn.:23 2 . 4 2.1 1.9 Pacific: Stn 24 2.5 2 .2 1.9 Pacific: Stn 30 2 . 4 2.0 1.7 * Sample size for each class was 5 except for Indian Arm, where 10 of each sex and 10 stage-V copepodites were measured. TABLE V PROSOME ANALYSIS FORM (Sex) SEG.l/SEG.1-5 SEG.2/SEG.1-5 SEG.3/SEG.1-5 SEG.4/SEG.1-5 SEG.5/SEG.1-5 LARGE N _ 34 N = 34 N = 34 N = 34 N 34 (females) X re0.45 X = 0.20 X = 0.13 X 0.12 X = 0.10 s — 0 .013 s _ 0 . 0 0 7 s = 0 . 0 0 7 s — 0 . 0 0 5 s a s 0 . 0 0 5 SMALL N — 35 - N — 35 N 3 5 N _ 3 5 N — 35 (females) X a s 0.48 X 0 .19 X = 0 .13 X _ 0.11 X a s 0.10 s _ 0 .013 s = 0.011 s 0.009 s 0.003 s a s 0.008 LARGE N — 3 5 N — 35 N _ 35 N — 3 5 N a s 35 (males) X = 0 .52 X = 0.16 X — 0.12 X 0.11 X s= 0.09 s = 0.014 s ss 0.010 s 0 . 0 0 6 s — 0.004 s ss 0.006 SMALL N — 3 5 N _ 3 5 N — 3 5 N — 3 5 N a s 3 5 (males) X = 0.52 X _ 0 .17 X = 0.12 X == 0.11 X = 0.09 s = 0.020 s 0.011 s r t 0.008 s as 0.008 s ss 0.009 LARGE N _ 2 5 N — 2 5 N — 2 5 N — 2 5 N a s 2 5 (G-Y) X _ 0.45 T 0.20 X = 0 .13 X = 0.12 X s= 0.10 s a s 0.012 s _ 0.011 s _ 0.009 s SB. 0.007 s 0 . 0 0 5 SMALL N — 2 5 N — 25 N — 2 5 N _ 2 5 N _ 2 5 (C~Y) X _ 0.4? X _ 0.19 X = 0 . 1 3 X _ 0.12 X a s 0.09 s = 0.017 s — 0.014 s = 0.010 s S= 0.011 s — 0.007 contrast to the more protuberant head of comparable stages of the Small Form (Figs. 8 and 9). The males of both forms have head shapes that are more protuberant than females and. stage-V's, but the degree of protuberance differs between males of each form (Fig. 10). The results of head shape measurements using the method of regression are presented in Fig. 11. The distribution patterns for females and stage-V's show the greatest difference, a fact that may also be determined from the photographs of the animals. The males have more similar distribution patterns, but the degree of spread is much smaller, possibly indicating a lesser degree of variation among males within each form. Table VI summarizes the statistical results for the head shape data. A regression analysis where head shape was considered the dependant variable and prosome length the independent variable failed to show any significant relationshipbbetween these two features. The conlusion is that head shape is independent of size.' Urosome Width and length measurements of each urosome segment were made on 2? males and 27 females of each form. The segments were numbered consecutively with the proximal or genital segment designated number 1. Width to length ratios were calculated from the data. Mean values of the ratios for each segment were compared between the same sex of both forms. Segments 1, 2 and 3 differed between females, and segments 3 and 4 differed between Figure 8. Photograph of females: Small Form on left, Large Form on right. Note attached spermatophores. Figure 9. Photograph of Stage-V copepodites; Large Form on left; Small Form on right. • • M P ? * ' m Figure 11. Head shape distributions. Small Form (females) Large Form (females) Small Form (males) Small Form (stage-V) _ i - i i • * i -H Large Form (stage -V) i - i — i ' i ^  ' o. .05 .07 .09 .11 .13 Regression coefficient RESULTS OF T TEST ON HEAD SHAPES FORM SEX MEAN VARIANCE CALC. T T(.Ol) Large Form F 0.11 0.7 x 10-^ 11.69 2.66 Small Form F 0.08 1.4 x 10 Large Form M 0.0? o.6 x io-;* 6.64 2.66 Small Form M 0.06 0.4 x 10-4 Large Form C-V 0.11 2.0 x 5.14 2.66 Small Form C-V 0.08 3.0 x 10"^ TABLE VII ANALYSIS OF WIDTH/LENGTH RATIOS OF THE UROSOME SEGMENTS FORM SEX SEGMENT MEAN VARIANCE CALC.T T(.Ol) Large Form F 1 0.85 0.006 3.94 2.67 Small Form F 1 0.93 0 .006 Large Form F 2 1.14 0.002 7.36 2.67 Small Form F 2 1.28 0.008 Large Form F 3 1.41 0.010 5.38 2.6? Small Form F 3 1.56 0.011 Large Form M 3 1.11 0 .007 6.63 2.67 Small Form M 3 1.22 0.001 Large Form M 4 1.32 0.006 7.33 2.67 Small Form M 4 1.49 0.008 Flgure 12. Urosome ratios, distribution. 10. 5. 0 Small Form ( f e m a l e s ) urosome segment 1 10. 5. 0 Large Form (females) urosome segment 1 h u o' in1 d Small Form (females) u r o s o m e s e g m e n t 2 15. 10. 5. 0 L a r g e Form ( f e m a l e s ) urosome segment 2 10. 5-0 Small Form (females) urosome segment 3 1 I in d in o r Large Form (females) u rosome segment 3 10. 5. 0 Small Form (males) urosome segment 3 15. 10. 5. 0 Large Form (males) urosome segment 3 10 H 5^ 0 Small Form (males) urosome segment 4 O cn o < L a r g e Form (males) u rosome segment 4 — 1 T 1——I——i 1— i——I——I— I I 1 r 0.7 0.9 1.1 1.3 1.5 1.7 Rat i o of width/length t males. Results of the analysis are summarized In Table VII. The r a t i o s are plotted as histograms-in Figure 12. To ar-range the data into convenient class in t e r v a l s the r a t i o s were rounded to the nearest 0.1 before p l o t t i n g , although the stu-dent's " t " test was run on the data before rounding. A regression of the width/length r a t i o s on prosome length indicated the proportions were Independent of s i z e . Animals taken from various points along the range (Table I).were measured and analyzed i n the same manner. No apparent change i n proportions over the range sampled was evident. Swimming Legs In the l o c a l forms the inner surface of the f i r s t segment of the exopodites on the second and t h i r d swimming legs was curved i n some specimens and not i n others. I n i t i a l l y i t was thought that t h i s would be a distinguishing c h a r a c t e r i s t i c be-tween the two l o c a l forms. In f a c t , i t appears to be a feature that i s present or absent depending on the orientation of the l e g on a microscope s l i d e . Width and length measurements were determined and r a t i o s of width to length were calculated. No s i g n i f i c a n t difference i n these proportions was noted, and the degree of curvature can be misleading. However, i f the legs are observed before mounting under a cover s l i p , the curvature of t h i s inner border can be seen to change as the l e g i s turned. The degree of asymmetry i n the exopods of the f i f t h swim-ming legs of the males i s greater f o r the Small Form than f o r Large Form Smal l F o r m F i f t h s w i m m i n g legs (males) the Large Form ( F i g . 13). The r e s u l t s o f measurements and s t a t -i s t i c s a r e presented i n T a b l e V I I I . F i g u r e 14 shows the d i s t r i b u -t i o n s r e s u l t i n g from the r a t i o of l e n g t h of r i g h t exopod/length of l e f t exopod f o r the two forms. When r e g r e s s e d on prosome l e n g t h , the r a t i o I n d i c a t e d t h a t the degree o f asymmetry, between the l e f t and r i g h t exopodites was independent of s i z e . The r e s u l t s of the r a t i o s where the i n d i v i d u a l exopod seg-ments of the l e f t f i f t h l e g were d i v i d e d by the sum of the le n g t h s of prosome segments 4 and 5 a r e presented i n T a b l e IX A. The r e -s u l t s i n d i c a t e t h a t the p r o p o r t i o n a t e l e n g t h o f segment 1 and of segment 2 of the l e f t exopod change s i g n i f i c a n t l y between the two forms (Table IX B ) . The p r o p o r t i o n a t e l e n g t h of segment 3 does not v a r y s i g n i f i c a n t l y . The toothed Calanus spp. have been d i v i d e d i n t o two groups on the b a s i s of the r e l a t i o n of width t o l e n g t h of the f i r s t and second segments of the l e f t exopods of the f i f t h l e g s of males (Brodsky, 1959). Values f o r t h i s r a t i o on specimens measured i n t h i s study are presented i n Table X. With the e x c e p t i o n of Queen C h a r l o t t Sound, the value s of Ta b l e X a r e a l l lower than those r e p o r t e d by Brodsky (1959) f o r P a c i f i c and S u b - A r c t i c Calanus spp., and a c e r t a i n degree of v a r i a b i l i t y i s e v i d e n t i n t h i s study when specimens from v a r i -ous p o i n t s a l o n g the range are measured. I t would appear t h a t d i f f e r e n t p o p u l a t i o n s of the same s p e c i e s can v a r y i n t h i s r e s p e c t . The degree o f asymmetry and the p r o p o r t i o n a t e l e n g t h s of the f i r s t two segments of the l e f t exopods i n the f i f t h l e g s f o r animals measured i n t h i s study d i d not var y w i t h l a t i t u d e . ANALYSIS OP ASYMMETRY IN FIFTH LEGS OF MALES — S t a t i s t i c a l Re-sults of the ratio: length right exopod/length l e f t exopod— FORM N MEAN VARIANCE CALC. T T(.Ol) Small 46 0.74 6 x lO"^ 21.03 2.617 Large 46 0.85 5 x^iO-^ TABLE IX A ANALYSIS OF PROPORTIONATE LENGTHS OF EXOPOD SEGMENTS IN THE FIFTH LEGS OF MALES FORM Small Large Left Exopod SEGMENT 1 SEGMENT 2 N=27 X=7.75 s=0.62 N=27 X=6.47 s=0.38 N=27 X=6.42 s=0.57 N=27 X=5.62 s=0.30 SEGMENT 3 N=27 X=4,04 s=0.34 1=27 X=3.82 s=0.73 FORM Small Large Right Exopod SEGMENT 1 SEGMENT 2 1=27 X=4.28 s=0.40 N=27 X=4.38 s=0.21 N=27 X=4.19 s=0.34 N=27 x=4.l4 s=0.19 S E G M E N T 3 N=27 x=5.05 s= 0 . 4 l N=27 X=4.99 s=0.27 T TEST ON THE PROPORTIONATE LENGTHS OF THE EXOPOD SEGMENTS ON THE LEFT FIFTH SWIMMING LEGS OF MALES FORM SEGMENT N MEAN VARIANCE CALC.T T ( . O : S m a l l 1 2? 7.75 0.38 9.12 2.67 Large 1 27 6.47 0.15 S m a l l 2 27 6 . 4 2 0.10 6 . 4 8 2.67 Large 2 27 5.62 0.32 S m a l l 3 27 4 . 0 4 0.12 1.43 2.67 Large 3 27 3 . 8 2 0.53 TABLE X WIDTHsLENGTH VALUES OF FIRST AND/OR SECOND SEGMENTS, LEFT EXOPOD, FIFTH SWIMMING LEG, MALES. LOCATION LARGE SMALL I n d i a n Arm, B.C. 1 : 2 . 4 1 : 2 . 4 G l a c i e r Bay, A l a s k a 1 : 2 . 7 Queen C h a r l o t t e Sound, B.C. 1 : 3 . 2 P a c i f i c S t a t i o n #10 1 : 2 . 8 P a c i f i c S t a t i o n #24 — 1 : 2 . 5 P a c i f i c S t a t i o n #30 1 : 2 . 9 P a c i f i c S t a t i o n #34 1 : 2 . 3 1 : 2 . 6 a T3 C 12-| 10. 8 6 4. 2. 0 0 12J 1 * J z 6. 4-2. 0 Large Form (males) Small Form (males) t o 0.66 0.70 0.75 0.80 0.85 0.90 Ratio of length right exopod/length left exopod ct -P-tr. CO 3 to K* O CD CD (5? ct 3 * co 0 4 1 ct CD CD co M • O •d o p< \ M CD tS ct 3 * H» CD M> ct CD X o o I Ox I The exopods of the f i f t h l e g s of females of both forms were s u b j e c t e d t o the same type of a n a l y s i s as were those of the males. The r e s u l t s of the r a t i o s where the i n d i v i d u a l l e n g t h s of the exopod segments were d i v i d e d by the sum of the len g t h s of prosome segments k and 5 i n d i c a t e t h a t the p r o p o r t i o n a t e l e n g t h of the d i s t a l or t h i r d exopod segment d i f f e r s between the two forms (Table XI A ) . Table XI B summarizes the " t " t e s t on the data. The d i s t r i b u t i o n s a re presented i n F i g u r e 15. A r e g r e s s i o n of t h i s r a t i o on prosome l e n g t h i n d i c a t e d t h a t the p r o p o r t i o n a t e l e n g t h of t h i s t h i r d segment i s inde -pendent of s i z e on the animal and f u r t h e r , no s i g n i f i c a n t v a r i a -t i o n w i t h l a t i t u d e was noted f o r e i t h e r form. S i n c e the sp i n o s e process on the a n t e r i o r d i s t a l s u r f a c e of the b a s i p o d i t e s on the f i f t h swimming l e g s appeared t o v a r y i n l e n g t h between the two forms, l e n g t h measurements were taken. The r e s u l t s a re pres e n t e d as a histogram ( F i g s . 16 and 17). T h i s s p i n e i s always s h o r t e r i n specimens o f t h e Large Form and i s sometimes present o n l y as a s m a l l bump. I n the Sm a l l Form i t i s always e v i d e n t and much l o n g e r . The d i f f e r e n c e i n l e n g t h s of t h i s process between the two forms i s s i g n i f i c a n t (Table X I I ) , and the valu e s of the l e n g t h measurements do not v a r y s i g n i f i -c a n t l y w i t h l a t i t u d e . A r e g r e s s i o n a n a l y s i s i n d i c a t e d that the l e n g t h o f t h i s process i s independent of s i z e o f the animal w i t h -i n the s i z e ranges measured. T h i s process i s found on males, females and Stage-V copepodites, and i s u s e f u l i n d i s t i n g u i s h i n g the two forms p a r t i c u l a r l y when the exopods o f r t h e f f i f t h l e g have been broken o f f . 5.0 5.5 6.0 6.5 Ratio of length exopod segment 3/sum lengths prosome segments 4+5 CD H o» •O CD ro o^ B 4 H CO CD CO h» -3 p. M - C t O 3 * P H -c t H C D P -H » C D C D M O c f d o C D a M o ca •d C D o cn p . . • \ •d o C O o s C D C O C D C D 3 c t C O i ON I Flgure 16. Femalest spinose process, length vs. frequency. Open bars indicate l e f t l e g . in — a E E i _ o LL o E if) mm c J L to a E E £ cn Y/////////M I-00 <M O J OJ CVJ O O J 00 (0 00 CD —I 1 1 1 1 1 1 1 1 1 1 1 1 r ^ C \ J O 0 0 ( O ^ C \ J O C \ I O 0 0 ( D - ^ O J O c O !_ U if) <u u O t_ Q. CU (fl o c O J — o s: cn c (U 9 | D n p ! A i p u i j o j a q u j n N 12-| 1 0 . 8 . * 6 . 4_ > 2 . 0 . Small F o r m (males) a C - 1 4 . o <- 124 <u ^ 1 0 4 ^ 8 . 6 . 4 . 2. O . •P—a-1 1 L I 1 L a r g e F o r m ( m a l e s ) - — i 1— 8 1 0 12 1 4 1 6 1 8 2 0 2 2 L e n g t h of s p i n o s e p r o c e s s ( m i c r o n s ) 2 4 —i— 2 6 2 8 o a *a a H CO fiT H> <D 3 co p- -O p ca CD H" H* O CD ca CD ct I-* 4 CD O 0} O • CD ca CO H C D 3 W ct V < C O CD CD 3 o I 0 0 I LEGS OF FEMALES LEFT EXOPOD FORM Small Large SEGMENT 1 N = 2? X = 3.92 s = 0.31 N = 27 X = 3.92 s = 0.16 SEGMENT 2 N X s N X s 26 3.87 0.30 27 3.63 0.18 SEGMENT 3 N = 26 X = 6.19 s = 0.41 N = 27 X = 5.64 s = 0.28 RIGHT EXOPOD Small Large N X x N X s 27 3.90 0.29 27 3.95 0.20 N = 23 x + 3 .88 s = 0 .28 N = 27 X = 3.62 s = 0.19 N X s N X s 22 6.14 0.51 27 5.65 0.28 TABLE XI B T TEST ON PROPORTIONATE LENGTHS OF EXOPOD SEGMENT 3 ON THE FIFTH SWIMMING LEGS OF FEMALES FORM Small Large Small Large N 26 27 22 27 MEAN VARIANCE  LEFT EXOPOD 6.19 0.17 5.64 0.08 RIGHT EXOPOD 6.14 0.26 5.65 0.08 CALC. T T(.Ol) 5.58 2.68 4.17 2.69 T TEST ON MEAN LENGTHS OF THE OF MALES SPINOSE PROCESS ON THE AND FEMALES FIFTH FORM SEX I MEAN VARIANCE CALC T T(.O ; LEFT LEG Sm a l l female 46 1 9 . 6 1 8 . 6 4 1 0 . 8 3 2 . 6 3 Large female 46 1 1 . 8 3 1 5 . 0 9 S m a l l male 46 1 8 . 4 0 7 . 0 7 1 8 . 6 5 2 . 6 3 Large males 46 7 . 6 1 8 . 4 2 RIGHT LEG Sm a l l female 46 2 0 . 1 1 1 0 . 8 1 1 2 . 3 8 2 . 6 3 Large female 46 1 1 . 1 2 1 3 . 6 1 S m a l l male 46 1 8 . 7 3 9 . 6 9 . 1 2 . 2 1 2 . 6 3 Large male 46 9 . 8 9 1 4 . 2 ? A map showing s t a t i o n p o s i t i o n s i s i n c l u d e d i n the m a t e r i a l s and methods s e c t i o n , w h i l e a l i s t of the s t a t i o n s w i t h t h e i r geo-g r a p h i c c o o r d i n a t e s i s presented i n Table I . F i g u r e 18 o u t l i n e s the d i s t r i b u t i o n s f o r both forms i n the a r e a sampled. The approximate boundaries f o r the r e g i o n of o v e r l a p , on the b a s i s of samples analysed i n t h i s study, a r e from 40° to 42° N l a t i t u d e . The Large Form was found i n samples from G l a c i e r Bay, A l a s k a , i n the n o r t h t o Cape Mendocine, C a l i f -o r n i a , i n the south. The S m a l l Form was found i n samples from Johnston S t r a i t , B r i t i s h Columbia, i n the n o r t h to San Diego, C a l i f o r n i a , i n the south. No samples were a v a i l a b l e from the west coast of Vancouver I s l a n d , and i t must be assumed t h a t the n o r t h e r n extent of the Small Form occurs i n t h i s r e g i o n . Temperature and s a l i n i t y data from s e l e c t e d s t a t i o n s were used to c h a r a c t e r i z e the p h y s i c a l environment a l o n g the p o r t i o n s of the ranges of both forms covered by t h i s study. S t a t i o n s l o -cated i n the i n l a n d waters and f j o r d s were not used because these r e g i o n s are g r e a t l y i n f l u e n c e d by i n s h o r e processes (e.g., freshwater r u n - o f f ) which makes d i r e c t comparison to open ocean s t a t i o n s d i f f i c u l t . Temperature and s a l i n i t y data from s e v e r a l s t a t i o n s a l o n g the outer c o a s t were omitted f o r the sake of c l a r i t y i n the diagrams. Such s t a t i o n s d i d not d i f f e r from r e s p e c t i v e adjacent s t a t i o n s , and the hydrographic p a t t e r n de-p i c t e d by the p l o t t e d s t a t i o n s i s r e p r e s e n t a t i v e f o r the time of the survey. Figure 18. Map showing d i s t r i b u t i o n of both Large and Small Forms. Horizontal s t r i a t i o n s indicate range of Large Form; v e r t i c a l s t r i a t i o n s indicate range of Small Form. Figure 1 9 . T, S diagram o f west coast data. 0 0 p a n E D o u — a B ! u >, o co z • </> a z «3 c > 1) O g-8 o U E 2 o ; L. 1 / 1 a c a u _ - u ^ < 5 U U o O C OO GO U F i g u r e 20. T, S, P diagram of west coast data. C i r c l e s i n d i c a t e Large Form; squares i n d i c a t e Small Form. Station Pacific 34, located inshore at Cape Mendocino, was plotted to show the effect of upwelling in the Immediate region. No stratified plankton tows are available for this station although a vertical haul revealed the presence of both forms. A l l other stations plotted Included stratified plankton tows taken in conjunction with hydrographic samples. Plots of temperature and salinity for the stations are presented after the method of Bary (1963) with the exception that the vertical as well as the horizontal changes in both fac-tors are considered (Fig. 1 9 ) . Arbitrary boundaries indicate the major changes in hydrographic characteristics In the hori-zontal direction. Using the method. ofTBary (1964), these bound-aries are then superimposed on the temperature-salinity-plankton (TSP) diagrams (Fig. 20) to Indicate the general association between the water masses and the two forms of Calanus. In interpreting the T-S diagram (Fig. 19) , i t should be recalled, that the Alaskan and northern British Columbia stations were taken in August whereas those off the coast of the continent-al United States were taken in February. The seasonal effect, with respect to temperature and salinity, is mainly in the, sur-face waters with the deeper water off Alaska similar with respect to temperature to the water north of Cape Mendocino but slightly more dilute. Four main hydrographic regions are defined (Fig. 1 9 ) . The f irst includes the relatively cool, dilute water off southeastern Alaska and northern British Columbia. The second includes the water off the coast of the continental United States, from the mouth of Juan de Fuca to a point approximately 60 miles north of Cape Mendocino, California, and is characterized by slightly more saline water. Deeper water in this area differs from the more northern water in the somewhat higher temperatures. The third region is in the vicinity of Cape Mendocino. The water is markedly warmed in the upper 100 meters and the salinity of the surface and sub-surface layers is notably higher. The fourth region includes the stations south of Cape Mendocino to San Diego and is characterized by warm relatively saline water. The vicinity of Cape Mendocino represents a region of change between the northern and southern waters, and appears as a transitional zone on the T-S diagram (Fig. 19). Station Paci-f ic 14, about 40 miles north of Cape Mendocino, is similar to the stations of the second region defined above. Station Paci-f i c 15, off Cape Mendocino, and Station Pacific 17, about 60 miles south, are similar to each other but distinctly different from the more northern stations with regard to temperature al-though the salinity of the surface and sub-surface water is slightly higher. Station Pacific 18, which is approximately 50 miles south of Pacific 17, has the characteristics of the more southern stations of the fourth region. There is l i t t l e change in properties between Station 18 and Station 30 off San Diego. Two of the stations plotted are different from the others in the respective regions. Pacific St&tion l , in the mouth of Juan de Fuca Strait, is characterized by relatively cool and dilute water in the upper 75 meters, probably a manifestation of the large amount of freshwater run-off from the Fraser River (Tully, 1942; Lane, 1962). Below this depth, the temperature-salinity plots are similar to those characteristic of the Pacific coast of Washington. Station Pacific 34 is inshore of Pacific 15 off Cape Mendocino, hut i t is different from the latter, being characterized by water similar to that found deep-er at the more northern stations. The seemingly anomalous qualities are probably the result of localized upwelling near shore. The Large Form of Calanus sp. (Shan, 1962) is commonly found throughout the water of region 1 (Fig. 20) with the high-est concentrations in the warmer surface layers between approxim-ately 9 and 1 2 ° C. In region 2 i t is present in surface, sub-surface and deep water. In region 3 the abundance of this form drops sharply to a single occurrence in the sub-surface water. In region 4 the large form is absent. The Small Form of Calanus sp. (Shan, 1962) is entirely ab-sent -from region 1 (Fig. 2 0 ) . It Is found throughout region 2 but in low densities with the exception of one surface sample from the coast of Oregon (Pacific Station 9) in which the cal-culated concentration was approximately 100 animals per cubic meter. The Small Form is present in region 3 in an abundance similar to region 2 . In region 4 i t is present in a notably higher density in the upper 100 meters. The figure of 100 animals per cubic meter, as determined for the surface sample at Station Pacific 9 , appears anomalous in contrast to the abundance at other levels on the same station and to the abundance at other stations in the immediate area. The phenomenon of encountering localized high concentrations occurred occasionally in Indian Arm, where sampling was more complete particularly when the same station was sampled period-ically over a 24 hour period. During one such sampling period an estimated 3000 animals per cubic meter was taken from a near surface tow, and yet in other sampling periods in the same 24 hour day the total number of animals per cubic meter integrated over the whole water column was much less than this figure. In this study such occurrences were more the exception than the rule and may be attributed to some concentrating effect such as the horizontal convergence of several water currents or possibly a localized upwelling. Yearly Presence and Density Analysis of vertical hauls and horizontal tows over a period of 1 5 months revealed the presence of both forms in Indian Arm throughout the year and eliminated the possibility that the two forms were seasonal morphological variants. Figure 21 shows the total animals per cubic meter for each month. The greatest fluctuations In abundance correlate with the l i fe cycle. Since only adults and Stage-V copepodites were counted, fluctuations in abundance were expected during periods when younger stages of both forms predominate, but such periods appear to exist for a short time. Fluctuations of smaller magnitude may be due to sampling error, predation, and possibly emigration and Immigra-tion. In addition, the Small Form appears to be more abundant than the large form throughout the year (Shan, 1962). Yearly Cycles and Periods of Breeding Figure 22 shows the fluctuation in abundance of adults and Stage-V copepodites for both forms over a period from October 1966 to April 1968. Figure 23 presents the fluctuation in adults of the two species on a percentage basis emphasizing the different periods of breeding. For any particular month the total number of adults of both species was determined, and then the percentage of that total represented, by the Large Form or the Small Form was calculated. Figure 21. Total animals/ / month (both Forms; Indian Arm only). F i g u r e 22. Y e a r l y c y c l e s both a d u l t s and stage-V's. Large Form adults reach a peak ln abundance in February (Fig. 2 3 ) . Thereafter the abundance of adults drops and, through-out the remainder of the year, the adult population is mainly fe-male. The Stage-V copepodites of the Large Form undergo a fluc-tuation in abundance that is the inverse of that of the adults.. An exception occurred in October 19^7, but this Is believed to be due to net sampling error (Fig. 2 2 ) . October was the one month in which ship time did not permit a complete vertical haul from near the bottom to the surface; as a result the net only sampled the upper 150 meters, 70 meters short of the-bot-tom, and the majority of the Stage-V population was probably in-completely sampled. It wi l l be seen below that the Stage-rV of the Large Form generally occupies the near bottom water layers especially during mid-day when the sample was taken. Small Form adults reach a peak of abundance in March', April or May, and again around September. The fluctuation in abund-ance of the Stage-V copepodites Is nearly Inverse to that of the adults. The period of sampling covers 19 months so that one complete yearly cycle with parts of the previous and parts of the succeed-ing yearly cycles are shown. The low numbers of adults for both species from October and November to January and February is re-peated and thus the results seem to be consistent. The pattern of increase in adults for both species appears to repeat itself , and the respective times within each species for the onset of this increase are similar in early 1967 and early 1968. Data o b t a i n e d from the d i s t r i b u t i o n a l study was used f o r a spot check of o t h e r p o p u l a t i o n s of both forms. The o b j e c t i v e was t o determine i f these p o p u l a t i o n s were i n a b r e e d i n g or non-breeding s t a g e . Assuming t h a t a b r e e d i n g population!) has a p r o p o r t i o n a t e l y h i g h e r number of a d u l t s than Stage-V copepo-d i t e s , the d e t e r m i n a t i o n of a b r e e d i n g or non-breeding popula-t i o n was based upon the r a t i o : number of a d u l t s to number of Stage-V copepodites. The monthly s e r i e s from I n d i a n Arm was used as a b a s i s f o r comparison a n d ' i s summarized, i n T a b l e X I I I . The c r u i s e t o A l a s k a i n August of 19&5 encountered the Large Form o n l y . The r e s u l t s of the r a t i o s are presented, i n T a b l e XIV. N e a r l y a l l the s t a t i o n s a n a l y z e d have a p r o p o r t i o n -a t e l y g r e a t e r number of Stage-V copepodites than a d u l t s . The p o p u l a t i o n of the Large Form i n I n d i a n Arm has a s i m i l a r pro-p o r t i o n f o r t h i s time of year. S t a t i o n P a c i f i c A d i f f e r s not-a b l y i n t h i s r a t i o from the o t h e r s , and i t i s b e l i e v e d t h a t t h i s i s due to incomplete sampling. Other s t a t i o n s i n the r e -g i o n of P a c i f i c A show the Stage-V's t o be i n g r e a t e r propor-t i o n . The s t a t i o n depth a t P a c i f i c A was approximately 900 meters, but the nets o n l y sampled down to 290 meters. Ninety-nine percent of the a d u l t s were found i n the upper 12 meters. S i n c e the Stage-V copepodites of t h i s form occur r e l a t i v e l y deep and i n I n d i a n Arm they a r e g e n e r a l l y found below the maj-o r i t y of the a d u l t s , the same s i t u a t i o n may have p r e v a i l e d a t P a c i f i c A w i t h the r e s u l t t h a t the nets f a i l e d t o sample the t o t a l p o p u l a t i o n e f f e c t i v e l y . Sumner S t r a i t had equal numbers of a d u l t s and S t a g e - V s . Based on the p r o p o r t i o n s observed a t the other s t a t i o n s of t h i s c r u i s e , i t i s p o s s i b l e t h a t the pop-u l a t i o n a t t h i s s t a t i o n was near the end of i t s b r e e d i n g season. The r e s u l t s of the a d u l t Stage-V r a t i o s f o r the two c r u i s e s to i n l e t s of B r i t i s h Columbia i n June- 1966 and June 1967 are summarized i n Table XV. Both forms were found a t some of the s t a t i o n s , e.g. ,. S u t i l Channel and Johnstone S t r a i t . The n o r t h -ern boundary of the Small Form was found d u r i n g these c r u i s e s and the S u t i l Channel s t a t i o n was measured twice thus e n a b l i n g a check on the c o n s i s t e n c y of the f i n d i n g s from one year to the next. In S u t i l Channel the Large Form Stage-V copepodites p r e -dominated i n both y e a r s . T h i s p r o p o r t i o n i s s i m i l a r to I n d i a n Arm f o r the Large Form a t t h i s time of the year. F o r the Small Form the a d u l t s predominated or were equal i n p r o p o r t i o n to the Stage-V's which i s a p a t t e r n s i m i l a r to t h a t f o r I n d i a n Arm a t t h i s time of year. Since the time of sampling i n S u t i l Channel i s one month e a r l i e r i n 1967 than 1966, the r a t i o s might be ex-pected to vary somewhat. The trend of more Stage-V*s and fewer a d u l t s i n the p o p u l a t i o n of Large Form i s s i m i l a r f o r both y e a r s . W i t h i n the p o p u l a t i o n of the Small Form the r a t i o o f a d u l t s : Stage-V changes n o t a b l y i n the J u l y I966 and June 1967 samples (Table XV). I t i s c o n c e i v a b l e , t h e r e f o r e , t h a t the change f o r t h i s form i n S u t i l Channel i s due to t h i s type of p o p u l a t i o n f l u x r a t h e r than sampling e r r o r . F u r t h e r , the trend from June to J u l y i s toward fewer a d u l t s and more Stage-V's i n both Indian Arm and S u t i l Channel. THE PROPORTIONS OF ADULTS TO STAGE-V COPEPODITES FOR INDIAN ARM MONTH LARGE FORM SMALL FORM J u l y 1966 1:18 4:1 October 1966 1:70 1:7 November 1966 1:113 1:35 December 1966 1:109 1:125 January 1967 1:5 1:67 February 1967 1:1 .1:36 March 1967 69:1 1:2 A p r i l 1967 1:1 1:1 May 1967 1:13 2:1 June 1967 1:14 5:1 J u l y 1967 1:22 1:2 August 1967 1:24 2:1 September 1967 1:18 1:2 October 1967 1:21 1:9 November 1967 1:48 1:50 December 1967 1:20 1:82 January 1968 1:7 1:44 February 1968 3:1 1:21 March 1968 46:1 1:2 A p r i l 1968 1:2 17:1 PROPORTION OP LARGE FORM ADULTS : STAGE-V COPEPODITES. CRUISE TO ALASKA - AUGUST 1965 STATION RATIO OF ADULTS G l a c i e r Bay 1:49 I c y S t r a i t 1:7 P a c i f i c A 8 :1 P a c i f i c B 1:8 P a c i f i c C 1:12 Lynn Canal 1:6 P a c i f i c F 1:4 Sumner S t r a i t 111 I n d i a n Arm (Aug. 1967) 1:24 PROPORTION OF ADULTS, J STAGE-V COPEPODITES CRUISES TO INLETS OF BRITISH COLUMBIA — JULY 1966, JUNE 1967 RATIO OF STATION FORM ADULTS:STAGE-V S u t i l Channel Large 1:8 (1966) Small 1:1 S u t i l Channel Large 1:6 (1967) Small 7:1 Queen C h a r l o t t e S t r a i t Large 5*1 (1967) J o h n s t o n e S t r a i t Large 4:1 (1967) *Small 3:1 Knight I n l e t Large 1:30 (1967) I n d i a n Arm Large 1:18 ( J u l y 1966) Small 4:1 I n d i a n Arm Large 1:14 (June 1967) S m a l l 5'1 I n d i a n Arm Large 1:22 ( J u l y 1967) Small 1:2 *Based on only 13 specimens — see t e x t . In Johnstone Strait, June 1967, only 13 adult specimens of the Small Form were found whereas nearly 1000 Large Form were encountered in the same sample. Adults of the Large Form pre-dominated, unlike the pattern in Indian Arm for this time of year. Since the Large Form outnumbered the Small Form 76 :1 , the fact that adults of the latter also predominated at this station is probably insignificant with regard to interactions such as interbreeding and competition for food between adults of both forms. This region is the northern boundary in the range of the Small Form, and the presence of suchllow numbers may indicate that the Johnston^ Strait population is not resi-dent but in fact an immigrant population derived from a resident population further south. The tides in the area are strong, and as a result may have a pronounced effect in transporting planktonic organisms some distance from their actual breeding populations. The strong turbulent tidal action in the narrow passages is an obvious mechanism for mixing the northern waters of Queen Charlotte Strait and Queen Charlotte Sound with the southern waters of upper Strait of Georgia. This action would con-ceivably contribute to the dilution of environmental factors essential to the survival and or reproduction of the Small Form. The lack of Small Form populations north of Johnstone Strait indicates these waters are different in character from the more southerly waters. The conditions which prohibit sur-vival and reproduction of the Small Form in Queen Charlotte Strait are present to a degree in the Johnstone Strait region and contribute to the dilution of the favorable conditions in the waters of the Strait of Georgia. As a result, the popula-tions of the Small Form appear diluted in the sense that popu-lation densities drop drastically in Johnstons Strait. The Large Form was the only form of the two encountered in Queen Charlotte Strait in June 1967. The adults of this popu-lation were greater in proportion to the Stage-V1s, as they were in Johnstone Strait, but dissimilar to the proportion in Indian Arm. In neighboring Knight inlet, the Large Form, was the only one noted, but in this region the Stage-V copepodites made up the greatest proportion of the population at this time, as they do in Indian Arm in June. The ratios for the cruise along the west coast of the U.S.A. in February 1966 are summarized in Table XVI. During this cruise the southern boundary of the Large Form was estab-lished. No data ajre available for Indian Arm in February 1966, but since the Indian Arm cycle appears to repeat itself , i t is probably that the ratios determined for February 196? and Feb-ruary 1968 are reasonable estimates of the pattern prevailing in February 1966. From Station Pacific 2, off the northwest coast of the state of Washington, to Station Pacific 34, off Cape Mendocino, California, adults of the Large Form tended to predominate in-creasingly toward, the southern boundary of its range. Adults of this form predominate or are equal In proportion to stage-V copepodites In Indian Arm at this time of year. PROPORTION OF ADULTS : STAGE-V COPEPODITES EASTERN PACIFIC CRUISE OF FEBRUARY 1966 RATIO OP STATION FORM ADULTS : STAGE-V P a c i f i c 2 Large 1:2 S m a l l 1:20 P a c i f i c 4 Large 4:1 Small 1:2 P a c i f i c 7 Large 22:1 P a c i f i c 34 Large 71:1 S m a l l 2:1 P a c i f i c 33 S m a l l 1:4 P a c i f i c 23 S m a l l 1:2 P a c i f i c 29 S m a l l P a c i f i c 30 S m a l l 3*1 I n d i a n Arm Large 1:1 (February 1967) Small 1:36 I n d i a n Arm Large 3:1 (February 1968) S m a l l 1:21 For the same range of stations, Stage-V's of the Small Form predominated in the populations sampled; this proportion is similar to Indian Arm in February. Off Cape Mendocino, however, the Small Form adults predominated, but they outnum-bered the Large Form 89:1. As in Johnstone Strait, where the Small Form was outnumbered by the Large, there is probajbly l i t t l e significant interaction between adults of both forms when one greatly outnumbers the other. South of Cape Mendocino, Small Form Stage-V's predominated in the populations off Central California. The reverse is true for the populations off southern California, where the adults predominated, in stations from Santa Barbara Channel to San Diego. Comparing these results to those for Indian Arm, i t was noted that in regions where both forms occur together, the respective ratios of adults:Stage-V's were similar to those for Indian Arm. South of the overlap, the ratio of adults: Stage-V's for the Small Form was dissimilar to the ratio found for Indian Arm. As for the Large Form, however, the proportionate number of adults increased torward the southern part of the range. The data indicate;, that the onset of the breeding period starts earlier at the southern end of the range for both forms. In regions of overlap, the l i fe cycles in general appear to be similar to those for the Indian Arm populations, but outside the overlap the breeding periods may differ. Analysls of Moulting Rates; Stage-V to Adult The moulting rates in several temperatures and in abundant food are presented in Figure 24. In the controls (no food) the time to 50 percent moulting was consistently greater than 20 days, and often over the experimental period cfr30 days, less than 50 percent of the'animals moulted. Experiments in at least two different temperatures were carried out during each experimental period so that a second control was available to check i f the reaction to temperature for that period was real. The number of days (Fig. 24) in which i t took 50 percent of the test animals to.moult from the fifth copepodite stage to the adult stage represents an average of three replicate ex-periments at each temperature for each form. The variation around each average was not more than 3 days. For both forms a notable change in rate occurs between 5 and 10° C. A slower rate of moulting at 10 and 1 5 ° C for the Large Form compared to the Small Form is indicated by the slope of the respective graphs (Fig. 24), but at 5° 0 , the Small Form appears to be somewhat slower compared to the rate in 10 and 1 5 ° C water. Between 5 and 10° C, the Small Form exhibits a more marked reaction, the period to 50 percent moulting being more than twice as long at the Iowerrtemperature. For the Large Form, over the same temperature range, this period is less. Figure 24. Moulting rate VB temperature. Each point repre sents an average time to $0% mounted gf 3 reglicate ex periments a t each temperature (5 , 10 , & 15 C). 24 animals were involved in each replicate. Large Form Small Form A"'t Station 9 in Indian Arm, measurements of temperature and salinity were made immediately prior to a series of strati-fied plankton tows. The purpose was to determine any possible division of the water column into distinct regions with respect to these two conservative oceanographic factors. Any regions thus defined might then be correlated to the vertical distribu-tion of the two local forms of toothed Calanus sp. The physical data was analyzed apart from the plankton data to avoid any possible bias. Temperature and salinity profiles are represented in groups to emphasize seasonal effects. The months are grouped according to the seasons demarcated by Gilmartin (1962) which are based primarily on the annual fluctuations in salinity. These seasons are as follows i 1) January to March' — late winter salinity minimum; 2) April to June — spring salinity maximum; 3) July to September — mid-summer salinity minimum; 4) October to December — early winter salinity maximum. Three main regions are evident upon inspection of the profiles (Figs. 25 - 2 9 ) . These regions are the surface layer, the intermediate layer, and the bottom or deep layer. The surface layer generally extends from the surface to approxim-ately 10 meters. For convenience i t is definedaas the region where salinity changes more than one part per thousand per 10 meters, and temperature changes more than 0 .8 degrees centi-grade per 10 meters. The deep layer generally starts around 125 meters and extends to the bottoms i t is characterized by a change in salinity of 0.1 parts per thousand or less per 25 meters and a change in temperature of 0.1 degree centigrade or less per 25 meters. The intermediate layer is defined as that region between the surface layer and the deep layer. The sur-face layer is subject to large fluctuations in temperature and salinity and is influenced to a large degree by the seasonal changes in temperature and freshwater runoff into the inlet. The intermediate layer exhibits a yearly variation with regard to both factors but the degree of variation is smaller relative to the surface layer. The deep layer is a relatively stable region which is influenced more by instrusions of denser water from the outside (Gilmartin, 1962). The three regions of the water column defined in this way, may represent three distinct water bodies in the sense of Bary ( I 9 6 3 ) . Their origin may be distinct and their qual-ity with respect to the survival and reproduction of both forms of Calanus sp. may differ to the extent that essentially three habitats are present. Under these circumstances morpho-logically similar forms or species with nearly identical eco-logical niches could conceivably coexist in a geographical sense, i . e . , both are found in a particular oceanographic re-gion. This would be an allopatric relationship with respect to the water column. Figure 25 represents the temperature and salinity condi-tions for February and March 196?. The three regions are o-21 22 i S ° / o o 23 24 25 26 27 25-5 0 -75-1 0 0 -&125- I Q x — x Apr. 1967 (5 .44 % o S f c . ) 150-1 o — o May 1967 (15.22 ° / o o S f c . ) 175j . . Jun. 1967 (5.92 % o S f c . ) Figure 27. T & S profiles for Indian Arm, Jul . , Aug., Sep., 1967. Figure 28. T & S profiles for Indian Arm O c , Nov., Dec, 1967. S ° /oo 21 2 2 2 3 2 4 2 5 2 6 27 0-1 ' 1 1 ' L. 2 5 J 5 OH 754 1 0 0 H & 125-1 1 5 0 J M5A 2 0 0 -x — x Jan. 1 9 6 8 (9.57 % o sfc.) o — o Feb. 1 968 (14.18 % o s fc. ) - Mar. 1 9 6 8 ( 1 7 . 0 8 ° /oo s fc . ) evident. A notable temperature change between the two months occurred in the intermediate layer illustrating the relatively short term fluctuations that can occur in this layer. .. The temperature and salinity profiles for the remaining months are represented in Figures 26 - 2 9 . The development of a large but gradual halocline and thermocline occurred from April to June 196?. In April 1967 there was l i t t l e ap-parent change in both temperature and salinity between 10 meters and 200 meters and any indication of an intermediate layer was nearly absent. In May 1967, a halocline developed and stratification was evident with respect to temperature. By June the thermocline and halocline appeared as a gradual change with regard to both properties, resulting in a T-S diagram for this month that appears as a straight line, down to a depth of 100 meters. There was l i t t l e appearance of stratification in the intermediate layer, and in this month, the deep layer warmed slightly. In the subsequent months the temperature of this deep layer varied l i t t l e from the June values. From July to September 196? stratification was evident in the intermediate layer, to a depth of 75 meters. Through these months the halocline became progressively steeper, tend-ing toward the salinity profile of February and March 1967. From October to December 1967 the halocline was less strongly developed, and the intermediate layer became progress-ively cooler indicating that the summer stratification was waning. Prom January to March 1968, the pattern was similar to February and March of 1967. The halocline was evident but not as pronounced, as earlier. The temperature c*Kangp:iin the inter-mediate layer was also relatively small. The upper level of the deep layer was displaced upward to 100 meters in June 1967 and from January to March 1968. The boundaries must not be considered as precise, however, asfc a zone of mixing of 5 to 10 meters or possibly more may exist between the layers. The temperature and salinity profiles from April to June 1967 are difficult to explain on the basis of sampling from one station. The nearly uniform conditions of both factors in April and the subsequent pattern in May and June suggest a possible intrusion of water from the out-side which gradually mixed with the resident water. The inlet is known to turn over periodically (Gllmartin, 1962) but any explanation over the sampling period described can only be built on speculation from knowledge about the previous history of the inlet. Mid-Day Vertical Distributions The mid-day distributions determined from monthly samples from February 1967 to March 1968 at station number 9 in Indian Arm are represented in Figure 30. Both forms are segregated into males, females, and Stage-V copepodites. The boundaries of the three water layers, as determined from the temperature and salinity conditions on the station for each month, are represented by stippling. Since a degree of mixing probably occurs at the interface between each layer, the boundaries are arbitrarily represented as regions at least 5 meters thick. The pertinent observations are as follows: 1. A l l the stages represented, with the exception of Large Form males and Stage-V copepodites, showed a reaction to the conditions present in June 1967. The abundance of each population was notably higher for this one month. 2. Large Form Stage-V's were notably higher in the water column i n April 1967. During this month the tempera-ture and salinity conitions over the water column between 10 meters and 200 meters were nearly uniform. Over the sampling period, only a slight vertical displacement was present in June 1967 for this stage. The majority of the ,stage-V population was present in the deep layer. 3. The adults and Stage-V copepodites of both forms ap-peared to react to the summer stratification. Gen-erally, they a l l occurred at lower levels between July and September 1967. 4. Large Form males are present for a comparatively short time, being present only in 7 of the total 14 months samples. Over most of the period the major-ity of the population occurred in the deep water layer? at other times the majority occurred near the boundary of the deep layer, reacting similarly to the Stage-V copepodites of this form in April 196?. 5. Large Form females generally appear higher in the water column than the males and Stage-V's. Small Form females are not distributed this way. 6. The majority of the population of Small Form adults and Stage-V's was found in the intermediate layer throughout the year. ?. Small Form males were absent for only 3 of the 14-months sampled, and thus were present for a longer period than the males of the Large Form. 8. The mid-day distributions of Large Form males show that the majority is always below the majority of the population of Small Form females. 9. Large Form females significantly overlapped the population of Small Form males over much of.the sampling period. From July to October, however, the majority of female Large Form were separate and below the majority of Small Form males. 10. The penetration of the upper boundary in June was not as pronounced for Large Form females. In con-trast more than 75% of a l l the Small Form stages studied were present in this upper layer in June. 11. Over the sampling period Large Form females were generally in the lower half of the intermediate layer, and 50% of the population was generally deeper than adults of the Small Form. 24-Hour Vertical Distributions Twenty-four hour stations taken during selected months over the same period as the noon hour samples provide a more detailed picture of the reaction of the animals to the pre-vailing water bodies, while indicating the relative length of time any particular stage of one form may overlap with that of the other. During the early part of the year the de-gree of overlap between males and females of the two forms be-comes important since at this, time there is a slight overlap in the breeding periods. If inter-breeding were to occur i t would be during this period. As in the mid-day distributions each form is broken down into males, females, and. Stage-V copepodites, and the distribu-tion of each considered separately. In cases where one stage was present in concentrations of less than 0 . 5 animals/cubic meter or entirely absent during one or more of the sampling times for the month considered, the stage in question was not plotted. Such low numbers cannot be accurately represented, with regard to vertical distribution and association with • Water layers. Also, low numbers of either sex were considered to be insignificant with regard to interbreeding. The 24 hour vertical distributions are represented in Figures 31-34. The boundaries of the water layers are repre-sented. as they were i n F i g u r e 3 0i f o r the mid-day d i s t r i b u -t i o n s . The dotted q u a r t i l e l i n e s r e p r e s e n t the d i s t r i b u t i o n of females w i t h a t t a c h e d spermatophores. The g e n e r a l p o i n t s t o be noted from these d i s t r i b u t i o n s a r e : 1. Both forms appear t o a t t a i n t h e i r deepest l e v e l dur-i n g the d a y l i g h t hours when v e r t i c a l m i g r a t i o n i s ev i d e n t . *" 2. With the e x c e p t i o n of May 1967. a l l stages of Small Form appear t o Migr a t e v e r t i c a l l y over a 24 hour p e r i o d . Large Form females migrate whereas, males and S t a g e - V s of t h i s form appear not t o do so. 3. The females of both forms migrate v e r t i c a l l y more c o n s i s t e n t l y than the males and S t a g e - V s . 4. F o r both forms, the peak or s h a l l o w e s t p o i n t a t t a i n e d d u r i n g a v e r t i c a l m i g r a t i o n i s g e n e r a l l y around 2400 hours. E x c e p t i o n s occur, however (e.g., August 1967, when Large Form females a t t a i n e d t h e i r s h a l l o w e s t p o i n t a t 1800). I n September 19&7 a n d January 1968 the peak of v e r t i c a l m i g r a t i o n was reached a t 1800 hours f o r m i g r a t i n g stages of both forms. I n March 1968 Large Form females reached a peak a t 1800 hours and a s i m i l a r t r e n d was noted f o r S m all Form females. With regard, t o Large Form a d u l t s and stage-V copepodites the p e r t i n e n t o b s e r v a t i o n s are: 1. Large Form females are generally higher than the males and Stage-V's of this form over a 24 hour period. 2. For most of a 24 hour period, the majority of the females are generally in the lower portion of the intermediate or in the upper portion of the deep layer. 3. Obvious overlaps occur between Large Form females and the population of Small Form adults and stage-V's. In February and March 1968, the majorty of the Large Form female population was below the majority of the Small Form male population during most of the sampl-ing period. 4. Large Form females with attached spermatophores were generally below the majority of the females. In January and February 1968 Large Form females with attached spermatophores were below the majority of Small Form males; the vertical distribution over-lapping that of the Large Form males. 5. During some months there was a tendency for<only part of the Large Form female population to migrate vertically over a 24 hour period. In September 1967 and. January 1968 vertical migration in this female population was not evident, 6. With the exception of May 1967, a l l stages of the Large Form appeared to stay below the surface layer. With regard to Small Form adults and stage-V copepodites the pertinent observations are: 1. The majority of adult and Stage-V populations occurr-ed in the intermediate layer over a 24 hour period. This pattern was consistent for a l l eight 24 hour stations. In January 1968 a portion of the female and Stage-V populations penetrated the deep layer but the majority appeared in the intermediate layer. 2. The female and Stage-V populations appeared to extend into the surface layer at the peak of the vertical migration during some months (e.g., May 19^7 and September 1967). The majority of the males stayed below the foundary of the surface layer. 3. The vertical distribution of the female population was similar to that of the males and stage-V's and not that of the Large Form females. . 4. The Small Form females with attached spermatophores occurred below the majority of the females, i . e . , most of those with spermatophores were within the lower 2$% of the total female population. It was this portion of the range that generally overlapped extensively with the range of the Small Form males. 5. The majority of the Small Form females were consist-ently above the majority of Large Form males. 6. The majority of the Small Form female population be-haved similarly when migrating. The only notable Time (hours) Feb 1967 12 18 24 06 12 12 18 24 06 12 12 18 24 06 12 12 18 24 06 12 i i i ' i i i * i 4 i 1 i 1 -I 1 i I i 50-100-150-200-ininilwtfflffiTi^ ^ IININIIIII^ NNJpMlffiMllll^ Large Form males Large Form females Large Form stage-V Small Form stage-V 18 24 06 12 May 1967 18 24 06 12 18 24 06 12 18 24 06 12 18 24 06 12 100-150 J I L - I I L_ Large Form females Large Form stage-V Small Form males Small Form females Small Form stage-V Time (hours) 18 24 06 12 18 24 06 12 i i i 100 150-200 July 1967 18 24 06 12 i I i _ 18 24 06 12 i i i _ 18 24 06 12 i i 1 Large Form females Large Form stage-V Small Form males Small Form females Small Form stage-V Aug 1967 12 18 24 06 12 12 18 24 06 12 12 18 24 06 12 12 18 24 06 12 12 18 24 06 12 j i i i - | i i i i i i i i i I i i ' ' 50-100-150 Large Form females Large Form stage-V Small Form males Small Form females Small Form stage-V Figure 33. 24 hour vert, distributions Sep. 67 and Jan. 68. ( U J ) L u d a Q exceptlon was in January 1968, when the lower 25$ stayed deep in the Intermediate layer following a pattern similar to Small Form Stage-V copepodites. Available Food When i t became evident from the samples that portions of the Large Form population were remaining in the deep layer for extensive periods of time, the question arose as to how the deep living animals maintained themselves. An available food source would be necessary to support them in some periods at least. In order to answer this question two chlorophyll anal-yses were run, one in February and one in March 1968. Feb-ruary was a month of low primary productivity at the surface. In contrast to this month, March 1968 was a period of rela-tively high primary productivity. Vis ib i l i ty from the surface was less than a meter, and the phytoplankton bloom consisted primarily of the diatom Thailassloslra sp. In March, fine mesh (#20) Clarke-Bumpus nets were used to sample the phytoplankton at the same standard depths as the zooplankton samples. The guts of specimens of"both"forms were analyzed to determine the type of food material'ingested. 'The results of the chlorophyll analyses are presented in Figures 35 arid 36. Since chlorophyll A occurs in a l l phyto-plankton (Chapman, 1962), i t was considered sufficient to analyze for this pigment only in order to indicate the rela-tive quantity of phytoplankton available. In February 1968 F i g u r e 35. C h l o r o p h y l l A d i s t r i b u t i o n f o r Feb. & Mar., I968, 100-3 10-d Indian Arm (stn. 9) Feb. 1968 ro E a o o u 100-3 10-d Indian Arm (stn. 9) Mar 1968 50 , 100 Depth (m) 150 200 there was a definite peak of chlorophyll A at the surface and a second obvious peak at 150 meters. Below 150 meters there was a relatively high concentration of chlorophyll A. In March 1968, the presence of a phytoplankton bloom at the surface was indicated by the high concentration of chloro-phyll A found there. Compared to the previous month there was nearly a tenfold increase in chlorophyll A at the sur-face. Other peaks occurred at 50. 100, and 200 meters. The indications are that viable phytoplankton cells do occur in the deep layer. Analysis of the Clarke-Bumpus tows revealed the presence of viable cells of Thallassiosira sp. and Skeletonema sp. in the deep layer and in the upper regions of the water column. Analyses of the guts of animals of both forms revealed the presence of Thallassiorsira sp. Breeding Experiments Breeding experiments following the scheme described in the materials and methods section, page 33» were conducted on four different occasions. The numbers of each sex of each form in-volved in the crosses are shown in Table XVII. Interformal fer-t i l izat ion never occurred. Intraformal fertilization was con-firmed in one Large Form female in the September I967 experiment. In the November I967 experiment, one Small Form female was fer-t i l ized. COMPOSITION OF BREEDING EXPERIMENTS m _ MONTH EXPERIMENT CONDUCTED Type of Cross Aug. 1967 Sep. 1967 Nov* 1967 Jan. 1968 Large Males 7 . 2 3 4 x • Large Females 27 20 3 21 Large Males 8 2 2 6 X Small Females 19 18 2 12 Large Females 27 20 3 23 X Sma l l Males 3 2 3 6 Sma l l Males 3 2 8 1 X Small Females 18 17 8 1 DISCUSSION The Large and Small forms of Calanus noted by Shan (1962) differ not only In external morphology, but in their distribu-tion along the west coast of North America, and in their gen-eral ecological relationships. Summary of the Differences The morphological differences between the two forms are similar to differences found, between recognized species of toothed Calanus from other regions (Marshall and. Orr, 1953; Brodsky, 1950? Jaschnov, 1955; Marshall, personal communica-tion). The obvious overlap in the ranges of the Large and Small Form is similar to that found for Calanus finmarchicus and C. helgolandlcus of the eastern North Atlantic and North Sea (Marshall and Orr, 1953). The most obvious morphological differences between the two forms are the overall length as reflected by the prosome length measurements, and the head shapes. Differences in the width to length proportions of the urosome segments are ap-parent from the analysis of the measurements, but these are hard to discern by eye. The genital and following two distal segments are different, in proportion, between the females; in the males the third and fourth segments from the proximal end of the urosome differ in length to width proportion. In the f i fth swimming legs, the results of the ratio formed by dividing the length of the right exopod by the length.of the left exopod express the varying degree of asymmetry between the males of the local forms. The fifth legs of females are symmetrical although a difference in the proportionate lengths of the third or terminal segments was evident after analysis. A character common to the males and females of both forms is the spinose process located on the distal surface of the bsipodites of the f i fth legs. It is notably longer In the Small Form and Is particularly useful in Identification when the exopods have been broken off the males of both forms. On these grounds, there is a possibility that the toothed Calanus from British Columbia are not identical from a taxonomic point of view. Comparison to Other Species Since the toothed Calanus of the Northeastern Pacific have frequently been synonymized with C. finmarchicus and. C.  helgolandicus of the North Atlantic, i t is important to dis-tinguish the animals from these two regions. The local toothed Calanus can be distinguished by the characteristics presented in the foregoing, whereas the distinctions from the North At-lantic species are based on descriptions and comments by Brodsky (1950 and 1965), Shan (1962), Jaschnov (1955)» Marshall and Orr (1950), and Sars (1903). On the basis of the protuberant shape of the anterior region of the cephalothorax, the curved row of teeth on each coxopodlte of the f i f t h swimming l e g s , and the g r e a t e r degree of asymmetry i n the f i f t h swimming l e g s of the males, the Small Form noted by Shan (1962) may be d i s t i n g u i s h e d from Calanus flnmarohlous (Gunnerus). The Small Form may be d i s -t i n g u i s h e d from C. h e l g o l a n d i o u s (Claus) by the shape of the a n t e r i o r r e g i o n of the cephalothorax and by the r e l a t i v e l e n g t h s of the segments of the l e f t exopod of the f i f t h swim-ming l e g s of males. The Large Form noted by Shan (1962) may be d i s t i n g u i s h e d from C. f i n m a r c h i c u s (Gunnerus) by the shape of the. row of t e e t h on the f i f t h swimming le g s of both sexes and. the degree of asymmetry of t h i s appendage i n the males. The Large Form i s e a s i l y d i s t i n g u i s h e d from C. h e l g o l a n d l c u s (Claus) by the shape of the a n t e r i o r r e g i o n of the cephalothorax and the degree of asymmetry i n the f i f t h swimming l e g s of the males. Of the d e s c r i p t i o n s f o r v a r i o u s s p e c i e s and, sub-species of t oothed Calanus, those of C. p a c i f i c u s c a l l f o r n i c u s Brodsky (1965) and C. g l a c l a l i s Jaschnov (1955) best a p p l y t o the toothed Calanus i n the waters of B r i t i s h Columbia. The d i a g -n o s i s i s based on the w r i t t e n d e s c r i p t i o n s , drawings, and r e -corded d i s t r i b u t i o n s presented, by the r e s p e c t i v e authors. The complete d e s c r i p t i o n s of the l o c a l forms g i v e n i n the appendix may be u s e f u l f o r r e f e r e n c e . I n the paper d e s c r i b i n g the sub-species Calanus p a c i f i c u s  c a l l f o r n i c u s f o r the f i r s t time, Brodsky (1965) compares two ot h e r s u b - s p e c i e s , C. p. oceanlcus and C. p. p a c i f i c u s . There i s l i t t l e doubt from the drawings alone/ t h a t the l o c a l Small toothed Calanus i s d i s t i n c t from the l a t t e r two su b - s p e c i e s , p a r t i c u l a r l y on the b a s i s of the s t r u c t u r e of the f i f t h , swim-ming l e g s of the males. Female Calanus p a c i f i c u s c a l i f o r n i c u s a re d i s t i n g u i s h e d by the protuberant a n t e r i o r r e g i o n of the cephalothorax, the r e l a t i v e l y s h o r t g e n i t a l segment which i s s t r o n g l y curved a l o n g the d o r s a l s u r f a c e , the number of t e e t h of the f i f t h l e g ( a v e raging about Zh and r a n g i n g from 20 t o 29) and the i n d i s t i n c t boundary between the e i g h t h and n i n t h segments on the antennules (Brodsky, 1965). I n the l o c a l S m all Form (Shan, 1962), the shape of the a n t e r i o r r e g i o n of the cephalo-thorax Is i d e n t i c a l t o the drawings g i v e n i n Brodsky's des-c r i p t i o n . Compared t o the other sub-species d e s c r i b e d by Brodsky (1965)» C. p. c a l i f o r n i c u s appears t o have a l o n g e r , more pronounced "forehead". The g e n i t a l segment i s n o t i c e -a b l y curved i n the l o c a l S m a l l Form, but a d i r e c t comparison i s d i f f i c u l t s i n c e a drawing of the g e n i t a l segment i n l a t e r a l view i s l a c k i n g i n B r o d s k y 1 s (1965) o r i g i n a l d e s c r i p t i o n . The number of t e e t h of the f i f t h swimming l e g s g i v e n by Brodsky agrees w i t h t h a t of the l o c a l S m a l l Form. The females a l s o have the i n d i s t i n c t a r t i c u l a t i o n between the e i g h t h and n i n t h segments on the antennules, but the same i s a l s o t r u e of the l o c a l Large Form. Male Calanus p a c i f i c u s c a l i f o r n i c u s are p r i m a r i l y d i s -t i n g u i s h e d by the l e n g t h of the l e f t endopod of the f i f t h swimmlng l e g s (Brodsky, 1965). U n l i k e the other sub-species d i s c u s s e d , t h i s endopod i s l o n g e r and extends beyond the f i r s t segment of the l e f t exopod, t e r m i n a t i n g w i t h i n the lower t h i r d of the second segment of the l e f t exopod. The r i g h t exopod does not extend beyond the a r t i c u l a t i o n between the second and t h i r d segments of the l e f t exopod but may extend t o the middle or d i s t a l t h i r d of the second segment of the l e f t exopod. The males of the l o c a l S m all Form a r e i d e n t i c a l i n these r e s p e c t s . The s i z e range of Calanus p a c i f i c u s c a l l f o r n i c u s males andrfemalesy as r e p o r t e d by Brodsky (1965)» agrees w i t h t h a t found f o r the S m a l l Forms i n t h i s study. The geographic range of Calanus p a c i f i c u s c a l l f o r n i c u s i n c l u d e s the west coast of the United S t a t e s (Brodsky, 1965). Animals c o l l e c t e d f o r t h i s study from the same r e g i o n not only f i t the m o r p h o l o g i c a l d e s c r i p t i o n f o r C. p. c a l l f o r n i c u s g i v e n by Brodsky (1965) but were a l s o m o r p h o l o g i c a l l y i d e n t i c a l t o the S m a l l Form d e s c r i b e d by Shan (1962) from I n d i a n Arm. On t h i s b a s i s , the Small Form i s b e l i e v e d t o be C. p. c a l l f o r n i c u s (Brodsky). The females of Calanus g l a c l a l i s are d i s t i n g u i s h e d by an evenly rounded a n t e r i o r r e g i o n of the cephalothorax and a compact,, r e l a t i v e l y broad body. The antennules reach to the end of the caudal f u r c a e , or the l a s t one or two segments extend beyond. The f i f t h swimming l e g s have a d i s t i n c t l y curved row of t e e t h near the middle o f t h e coxopodite although the curve i s somewhat d i s p l a c e d toward the p o s t e r i o r s u r f a c e of the segment (Jaschnov, 1955). T h i s l a s t f e a t u r e may vary w i t h temperature (Mathews, 1966). The t e e t h are r e l a t i v e l y l a r g e and b l u n t and v a r y i n number from 26 to 43 (Jaschnov, 1955)• The outer and i n n e r edges of the f i r s t segment of the exopods of the f i f t h swimming l e g s are n e a r l y p a r a l l e l as op-posed to the t r i a n g u l a r shape i n C. p a c i f i c u s . The males of Calanus g l a c i a l i s are d i s t i n g u i s h e d primar-i l y by the f i f t h swimming l e g s . The r i g h t exopod i s s h o r t e r than the l e f t , extending t o or s l i g h t l y beyond the a r t i c u l a -t i o n between the second and t h i r d segments of the l e f t exopod. The l e f t endopod does not reach beyond the middle of the second segment of the l e f t exopod. W i t h i n the l e f t exopod of the f i f t h l e g s , the f i r s t and second segments are n e a r l y e q u a l i n l e n g t h , but the t h i r d segment i s approximately 2/3 the l e n g t h of the second segment (Jaschnov, 1955). The l o c a l Large Form d i f f e r s from the o r i g i n a l d e s c r i p -t i o n of Calanus g l a c i a l i s Jaschnov (1955) i n being somewhat s h o r t e r and. having fewer t e e t h on the coxopodite of the f i f t h l e g . Most specimens of C. g l a c i a l i s , from Jaschnov*s (1955) work, have 30-35 t e e t h per l e g , whereas the m a j o r i t y of s p e c i -mens of the l o c a l Large Form had 22-27 t e e t h per l e g . Shan (1962) r e p o r t s t o o t h counts which agree w i t h those found i n t h i s study and a l s o mentions the i n a b i l i t y to d i f f e r e n t i a t e the two l o c a l forms on the b a s i s of number of t e e t h . The number of specimens counted i n t h i s study was 30, w h i l e the number counted by Shan (1962) was 82. The number of specimens used by Jaschnov (1955) i s not mentioned, and h i s v a i e s are expressed by percentages, but i f a low number of animals were used then h i s d i s t r i b u t i o n s could be incomplete. A h i g h e r number of counts of animals from the A r c t i c and Sea of Japan, where the s p e c i e s was o r i g i n a l l y d e s c r i b e d (Jaschnov, 1955), might r e s u l t i n d i s t r i b u t i o n s which would be more l i k e those of the l o c a l p o p u l a t i o n s . A check of the number of t e e t h i n the Large Form from v a r i o u s p o i n t s a l o n g the range i n t h i s study, f a i l e d t o show any s i g n i f i c a n t v a r i a t i o n w i t h l a t i t u d e . The Large Form of Shan (1962) appears t o Calanus g l a c i a l i s a lthough, u n l i k e C. p a c i f i c u s c a l l f o r n i c u s , the l e n g t h v a r i e s s i g n i f i c a n t l y w i t h l a t i t u d e ( F i g . 7 ) . T h i s could e x p l a i n Shan's (1962) n o t a t i o n t h a t , except f o r t h e i r s m a l l e r s i z e , the l o c a l Large Form appeared m o r p h o l o g i c a l l y s i m i l a r t o C.  g l a c l a l l s as d e s c r i b e d by Jaschnov (1955). Grainger (196l) r e p o r t s a s i m i l a r change i n mean l e n g t h f o r C. g l a c l a l l s In samples taken a l o n g the n o r t h e a s t coast of Canada from the A r c t i c Ocean to the G u l f of Maine. Grainger's samples range much f u r t h e r n o r t h than those from t h i s study, but he r e p o r t s a maximum l e n g t h i n i n d i v i d u a l s somewhat south of the n o r t h e r n extent of the range of the s p e c i e s . Animals i n the A r c t i c Ocean were s h o r t e r than those i n the area of Foxe B a s i n , Hud-son S t r a i t , and n o r t h Hudson Bay. The mean l e n g t h of s p e c i -mens from Foxe B a s i n was 3 .98 mm w h i l e the mean l e n g t h of those from the G u l f of Maine was 2,80 mm. S i n c e change i n l e n g t h of the prosome appears t o be much l e s s than i n the urosome segments i n preserved animals, pro-some len g t h s o n l y were used i n t h i s study t o r e f l e c t the o v e r a l l s i z e of each specimen. In order to make an approxim-at e comparison of prosome l e n g t h data w i t h t o t a l body l e n g t h d a t a the f o l l o w i n g r e l a t i o n s h i p s were d e r i v e d : F o r C. g l a c i -a l i s the prosome l e n g t h of females i s 0.74 of the t o t a l l e n g t h . For males and Stage-V copepodites the prosome l e n g t h i s 0.73 and 0.75 of the t o t a l body length', r e s p e c t i v e l y . I n t h i s study a change i n mean prosome l e n g t h of 0 .6 mm f o r females and 0 . 5 mm f o r males and Stage-V copepodites was recorded over the p o r t i o n of the range sampled a l o n g the North American west c o a s t . Jaschnov (1955) r e p o r t s C. g l a c i a l i s from the Sea of Japan and the Sea of Okhotsk as w e l l as a number of r e g i o n s a l o n g the A r c t i c coast ofc-the U.S.S.R. Jaschnov's l e n g t h measurements are g r e a t e r than those from G r a i n g e r ' s (1961) study, w i t h a range of l e n g t h s , f o r female specimens from the Sea of Japan, of 4 .3 - 5 .0 mm ( e q u i v a l e n t prosome le n g t h s are 3 .2 and 3*7 mm r e s p e c t i v e l y ) : f o r the Sea of Okhotsk, 4 . 5 - 5«2 mm ( e q u i v a l e n t prosome l e n g t h s a re 3 . 3 and 3 . 8 mm r e s p e c t i v e l y ) . Males and Stage-V copepodites a re somewhat s m a l l e r . The s p e c i e s has been r e p o r t e d from the B e r i n g Sea and l e n g t h measurements f o r females are s i m i l a r t o those r e p o r t e d from the Sea of Okhotsk (Jaschnov, 1958). I n the c e n t r a l North P a c i f i c , female G. g l a c i a l i s c o l l e c t e d from 3 1 ° 54' N, 154° 4 9 ' W, were r e p o r t e d t o have a l e n g t h range of 3*45 - 3 .84 mm ( e q u i v a l e n t prosome lengths are 2.56 and 2.84 mm r e s p e c t i v e l y ) (Park, 1968). Size variations on the order of 1 mm have been reported f o r the toothed Calanus sp. i n the Queen Charlotte area (Cam-eron, 1957)• I t i s assumed that these Calanus are C. g l a c i a l l s Jaschnov since no other species were noted from that region i n t h i s survey, and no others have been reported In the l i t e r a -ture other than the synonomy with C. finmarchicus. Cameron (1957) suggested that the s i z e v a r i a t i o n may be due to speci-mens from d i f f e r e n t broods. This statement i s based on the findings of Digby (1950), who reports that species producing more than one brood a season frequently show a size v a r i a t i o n i n adults from d i f f e r e n t broods, and such a v a r i a t i o n was found to be true of C. finmarchicus i n the v i c i n i t y of the B r i t i s h I s l e s . C. finmarchicus reaches maturity i n approxim-at e l y 28 days i n the waters around B r i t a i n , but t h i s period i s reported to be longer i n more northern waters (Digby, 1950). Cameron (1957) states that her c o l l e c t i o n s were made i n a period of 21 days and therefore i t was not l i k e l y . t h a t the 4dults from two broods were capturepl. • Further, she notes that s i z e v a r i a t i o n i n adults of l o c a l breeding populations were minimal, but she did note d i f f e r e n t s i z e ranges between breeding populations. Since the s i z e of C. g l a c l a l l s appears to increase i n colder northern waters (Jaschnov, 1958; Graing-er, 1961), i t may also be true that the s i z e may increase i n populations breeding i n the colder fpords of the B r i t i s h Col-umbia and southeast Alaskan Coasts. In regions around the Queen Charlotte Islands that are influenced by the r e l a t i v e l y warmer waters of the Pacific Ocean, the breeding populations of G. glacialis may appear smaller. On the basis of these findings It is evident that a size variation with latitude similar in magnitude to that described by Grainger (1961) occurs in the waters of the northeast Pacif-ic Ocean. As a result, the C. glacialis in Indian Arm are smaller than the specimens described by Jaschnov (1955) from more northern waters. Biochemical differences were also noted for the local species. Using the method of starch gel electrophoresis a difference of 2 out of 7 protein zones was demonstrated (Beh-rens, 1968) . This result helps substantiate the fact that good differences do exist, but any conclusion as to the taxo-nomic relationship on a biochemical basis must await further study. Distribution Calanus pacificus californicus has been reported from 23° N to 48° N along the west coast of the United States and Mexico (Brodsky, 1965) . The occurance of C. glacialis in the northeastern Pacific has been proposed by Jaschnov (1957) and Brodsky (1965)» and the C. finmarchicus type described by Campbell (1930) along the west coast of Canada is believed by Jaschnov to be C. glacialis. This Is based on Campbell's de-scriptions of the f i f th legs of the males (Jaschnov, 1957). A sample from Unimak Pass i n the Aleutians sorted in this study-confirmed the presence of C. g l a c l a l i s . The southern extent of C. g l a c l a l i s . along the west coast of North America, has been surmised to be slightly south of Cape Flattery, Washing-ton (Brodsky, 1965) . Neither of the two authors verify the occurrence of either species i n the inldnd waters of southern Br i t i s h Columbia, and the amount of overlap indicated for the two species is believed to be slight, covering about one de-gree of latitude between k?° and 48° N. The faunistlc boundaries established In this study ex-tend those presented above, particularly in the case of C.  g l a c l a l l s . Brodsky (1965) indicates the absence of C. p. callfornicus from two stations slightly south of Cape Cook on the west coast of Vancouver Island. Since this species Is present in the mouth of Juan de Fuca Strait, the northern boundary along the outer coast probably occurs slightly north of this point. In addition, C. p. callfornicus was not pres-ent in samples taken from Pacific station 2 located about 60 miles seaward of Cape Flattery, although Brodsky (1965) indi-cates i t s seaward occurrence farther south off the coast of California to be on the order of several hundred miles. The boundaries are subject to va r i a b i l i t y from several sources. They may fluctuate with season, currents, tides, and movements of water masses. Tides may be of particular concern in the inland waterway of southern Bri t i s h Columbia. Any one or a combination of hydrographic properties such as temperature and salinity may also be responsible for varia-tion in these faunal boundaries, especially i f the animals are associated with particular water masses or water bodies (Bary, 1964). In the Northeastern Pacific, the respective faunal boundaries for toothed Calanus spp. may reflect the water mass boundaries 6f:..'theotwO'4waterr,masses Indicated on Figures 19 and 20. As the limits of these water masses shift with time, so would the general distribution of toothed Calanus spp. be expected to shift. Since the two species cannot be easily distinguished in stages younger than the Stage-V copepodite, the stage of the l i fe cycle predominating in a population of one species in a given area becomes important. If such an area, sampled when the majority of the population of one species were in a stage younger than Stage-V copepodite, revealed no adults or Stage-V*s in the samples, then conceivably a false conclusion could be drawn about the exact distribution of that species. For a l l these reasons, the boundaries found from the samples in this study can only be considered as approximate. Distributional Ecology In terms of density of Stage-V copepodites and adults of Calanus glacialis and C. pacificus californicus there appears to be a difference in the associations with the water bodies illustrated in Figures 19 and 20. C. glacialis has greater population densities in the cooler, more dilute northern waters whereas C. p. c a l l f o r n i c u s occurs In g r e a t e r numbers i n the warmer, more s a l i n e southern waters. I n t e r p r e t & i o n of these hydrographic p r o p e r t i e s and f a u n a l d i s t r i b u t i o n s a l o n g the west coast of North America r e q u i r e s a g e n e r a l knowledge of the C a l i f o r n i a Current System. The main concern i n t h i s study i s t h a t p o r t i o n of the system between l a t i t u d e s 33° and 58° N. Of p a r t i c u l a r concern i s the cause of the marked, change i n p r o p e r t i e s around Cape Mendocino, and the i n f l u e n c e of the system i n g e n e r a l on the d i s t r i b u t i o n of both s p e c i e s . The southward, r e l a t i v e l y slow f l o w i n g branch of the A l e u t i a n or S u b - A r c t i c c u r r e n t i s known as the C a l i f o r n i a Current and normally occurs between l a t i t u d e s 48° and 23° N (Sverdrup, 1943). A second northward f l o w i n g branch of sub-A r c t i c water forms p a r t of the A l a s k a G y r a l ( I b i d ) . The water of the C a l i f o r n i a Current i s p r i m a r i l y sub-A r c t i c In o r i g i n , but as the system moves toward the south the s u b - A r c t i c water becomes mixed h o r i z o n t a l l y w i t h C e n t r a l North P a c i f i c water and both v e r t i c a l l y and h o r i z o n t a l l y w i t h E q u a t o r i a l P a c i f i c water (Sverdrup, 19-+3; Reid, 1958). In r e g i o n s of u p w e l l l n g i n the c u r r e n t system, water from the lower p a r t of the s u b - A r c t i c water mass mixes w i t h a ' t r a n s i -t i o n a l ' form of E q u a t o r i a l P a c i f i c water f l o w i n g n o r t h below 200 meters and i s c a r r i e d to the s u r f a c e (Reid, 1958). Sub-A r c t i c water i s c h a r a c t e r i z e d by low temperatures and low s a l i n i t i e s . The E q u a t o r i a l P a c i f i c water may be d e t e c t e d by i t s warmer temperatures and h i g h e r s a l i n i t i e s . A counter c u r r e n t i s a s s o c i a t e d w i t h the C a l i f o r n i a Cur-r e n t system. I t Is present over the year below 200 meters oc-c u r r i n g i n s h o r e of the southward, f l o w i n g S u b - A r c t i c water and r e p r e s e n t s a northward flow of E q u a t o r i a l P a c i f i c water. Dur-i n g p a r t s of the year, when winds from the n o r t h and,northwest a r e r e l a t i v e l y weak, i . e . , g e n e r a l l y from November t o January, t h i s counter c u r r e n t appears a t the s u r f a c e and i s known as the Davidson Current (Reid, 1 9 5 8 ) . D r i f t b o t t l e experiments have shown t h a t t h i s s u r f a c e counter c u r r e n t flows a t an e s t i -mated r a t e of 0 .5 knots (Reid, i 9 6 0 ) , and i t may extend as f a r n o r t h as Vancouver I s l a n d (Sverdrup, 1 9 4 3 ; R e i d , . 1 9 5 8 , I 9 6 0 ) . Other i n t e r m i t t a n t f e a t u r e s of the system are the seas-o n a l u p w e l l i n g , o c c u r r i n g i n s p r i n g and summer when winds from the n o r t h a r e s t r o n g e s t , and. the l o c a l i z e d eddy systems which 'Occur i n the s u r f a c e water (Reid, 1 9 5 8 , I 9 6 0 ) . The temperature and s a l i n i t y data presented i n t h i s s t u d y - f o r the s t a t i o n s a l o n g the outer coast r e f l e c t , the char-a c t e r i s t i c s of a t l e a s t two of the water masses i n v o l v e d i n the C a l i f o r n i a Current system. S i n c e the waters n o r t h of Cape Mendocino t o s o u t h e a s t e r n A l a s k a are r e l a t i v e l y c o o l and low i n s a l i n i t y , i t i s probable t h a t the water i s p r i m a r i l y S u b - A r c t i c . The s t a t i o n s o f f s o u t h e a s t e r n A l a s k a and n o r t h e r n B r i t i s h Columbia may be d i s t i n g u i s h e d , from the s t a t i o n s between Cape F l a t t e r y and. Cape Mendocino mainly on the b a s i s of s a l -i n i t y i n the upper l a y e r s and of temperature i n the deeper layers. The northernmost series of stations are'nearshore and the water represented on the T-S diagram may be Sub-Arctic water of the Alaskan Gyral which has become mixed to some extent with the waters of the Inside Passage. The water sampled along the coasts of Washington, Oregon, and northern California is probably sub-arctic for the most part since the California Current is broad in cross-section and. the sta-tions in this study were generally near the coast, away from the mixing effects with the warmer, more saline'Central North Pacific water. The presence of C. glaclalis in-these coastal waters may be an indication of their sub-Arctic origin. South of Cape Mendocino the temperature and salinity measurements are markedly different from the more northern stations. Since the stations were within the area where the Davidson Current Is known to exist, the warmer, more, saline water encountered, south of Cape Mendocino probably represents water of this northward flowing counter current. The inshore stations north of the cape reflect the characteristics of sub-Arctic water. The water around the cape appears transi-tional between the two main water masses and. is, probably a zone of mixing. During the time of the year when the cruise was taken (February) the extent and strength of the Davidson Current was probably past its seasonal peak andits northward extent less than has been recorded previously. ' Calanus glaclalis appeared in greatest abundance in sub-Arctic water. As the water mass became mixed around Cape Mendocino, the s p e c i e s dropped i n abundance and disappeared a l t o g e t h e r i n the water of the Davidson C u r r e n t . The presence of t h i s s p e c i e s i n the B e r i n g S t r a i t , Sea of Okhotsk, and Sea of Japan has been confirmed by Jaschnov ( 1 9 5 7 ) . In t h i s study i t was noted In a sample from Unimak Pass i n the A l e u -tians.. P a r t of the water forming the s u b - A r c t i c c u r r e n t i s be-l i e v e d t o come from an a n t i - c l o c k w i s e gyre i n the B e r i n g Sea, and c o n t r i b u t e s t o the f o r m a t i o n of the s u b - A r c t i c water through the Oyashio Current (Sverdrup, 1 9 4 3 ) . The s u b - A r c t i c water i s b e l i e v e d t o be formed by mixing of the Oyashio and Kuroshio waters. The eastward f l o w i n g and. e v e n t u a l b r a n c h i n g t o a northward.andsouthward flow, of the s u b - A r c t i c Current p r o v i d e s a means of t r a n s p o r t by which C. g l a c i a l i s c ould be c a r r i e d from the A r c t i c i n t o the North P a c i f i c and thence t o the west coast of North America. -I f samples i n t h i s study were taken i n s u b - A r c t i c water, i . e . , f u r t h e r o f f s h o r e , a t the s o u t h e r n p a r t of the d i s t r i b u -t i o n of C. g l a c i a l i s f then the southern boundary of d i s t r i b u -t i o n might p o s s i b l y be extended. As was the case i n t h i s study the Davidson Current was encountered and the s p e c i e s l o s t . The h i g h numbers found i n s u b - A r c t i c water, the t r a c e found i n the mixed water around. Cape Mendoclrio and the ab-sence i n the Davidson Current i n d i c a t e that C. g l a c i a l i s l i v e s in cool, dilute sub-Arctic water. As the sub-Arctic water becomes mixed with the other water masses a degree of change occurs beyond which the species cannot tolerate. In other re-gions, e.g., the North Atlantic, this species is generally found in cold relatively dilute water (Jaschnov, 1961). Since mixing of sub-Arctic water occurs inshore, with water of Equatorial origin, and. seaward, with water of Central North Pacific origin, the southern boundary of C. glaclalis may ac-tually be wedge shaped as mortality of the animals increases at the eastern and western boundaries of the sub-Arctic water. The effect would be a core of relatively unmixed sub-Arctic water penetrating to the south with a concurrent core of C.  glaclalis present until conditions are met which the animals cannot tolerate. C. pacificus callfornicus was present in greatest abund-ance in the relatively warm, saline water of the Davidson Current, but contrary to C. glacialls Its density dropped off sharply in the sub-Arctic water. Abundance of C. p. callf-ornicus south of Cape Mendocino as shown in this study is similar to density figures reported for C. helgoland1cus in the CALCOPI atlas number 2 in 1958 and 1959 (Fleminger, 1964). Since the majority of samples reported in this atlas are well below Cape Mendocino this species is most likely C. p. callf-ornicus Brodsky. Pleminger (personal communication) does recognize C. glaclalis as a separate species. The atlas also indicates that the highest concentrations occur near-shore between San Francisco and Los Angeles. Since sampling occurred at a time after the Davidson Cur-rent is usually at its peak, the generally low abundance of C. p« californicus in the sub-Arctic water north of Cape Mendocino is possibly an indication that those specimens present represent relics. It is possible that breeding popula-tions of this species do not occur along the coast of Washing-ton, Oregon and northern California since the number of Stage-V copepodites encountered in the region outnumbered the adults, but farther south the reverse was true. The copepodite Stage-V of Calanus is a hardy overwintering stage and wi l l with-stand environmental fluctuations and extremes that the other stages cannot tolerate (Marshall and Orr, 1955). If true for C p . californicus, the result would be that adults carried north by the Davidson Current would have a higher mortality rate than the Stage-V copepodites when the counter current breaks down and sub-Arctic water predominates: thus the adult to Stage-V ratio is altered in favor of the juvenile over-wintering stage. It has been shown for two copepod species off the Oregon coast that the seasonal cycle of currents and associated water bodies is influential on copepod distribu-tions (Cross and Small, 196?). Acartia danae was found dur-ing the winter in Davidson Current water, but in summer the concentration became less and a second copepod, Centropages  mcmurrichi, appeared in water of northern origin. During periods of change (the breakdown of the Davidson Current in late winter) sporadic.low density occurrences of both species were found (Cross and Small, 1967). The seasonal occurrence of A. danae o f f the coast of Washington i n w i n t e r has suggest-ed a p o s s i b l e use of t h i s s p e c i e s as an i n d i c a t o r of "southern water ( F r b l a n d e r , 1962). E c o l o g i c a l S t u d i e s i n I n d i a n Arm R e s u l t s of the I n d i a n Arm study show Calanus p a c i f i c u s  c a l l f o r n i c u s i n g r e a t e r abundance than C. g l a c l a l i s . F u r t h e r , the d e n s i t y of the former i s s i m i l a r t o t h a t found o f f c e n t r a l and southern C a l i f o r n i a . There i s l i t t l e doubt from the eco-l o g i c a l r e s u l t s t h a t C. p. c a l l f o r n i c u s can m a i n t a i n a breed-i n g p o p u l a t i o n i n t h i s i n l e t . S p e c u l a t i n g on the r e s u l t s of the d i s t r i b u t i o n a l survey, Calanus p a c i f i c u s c a l l f o r n i c u s ,1s e s t a b l i s h e d as a b r e e d i n g . p o p u l a t i o n o f f southern and c e n t r a l C a l i f o r n i a and i s a s s o c i -ated w i t h the Davidson Current water. The Davidson Current -p r o v i d e s a t r a n s p o r t mechanism of r e l a t i v e l y h i g h r a t e , i . e . , 0 . 5 knot (Reid, i 9 6 0 ) , which has the p o t e n t i a l t o c a r r y the s p e c i e s n o r t h t o the s t r a i t of Juan de Fuca. T i d a l c u r r e n t s and. deeper onshore flow of water c o u l d t r a n s p o r t the s p e c i e s i n t o the southern i n l e t s of B r i t i s h Columbia ( T u l l y , 1942; He r l i n v e a u x and T u l l y , 196l; Lane, 1962).. The s p r i n g and summer c o n d i t i o n s of the water bodies i n i n l e t s such as I n d i a n Arm are s u i t a b l e f o r breeding, growth, and s u r v i v a l of a d u l t s , m a u p l i i and. copepodite stages. The Stage-V copepodite i s capable of s u r v i v a l u n t i l the f o l l o w i n g s p r i n g when i t moults i n t o the a d u l t and b r e e d i n g occurs. The b r e e d i n g p o p u l a t i o n s of B r i t i s h Columbia and C a l i f o r n i a appear t o be connected by the Davidson Current. T h i s allows an i n t e r m i t t a n t c o n n e c t i o n > between the p o p u l a t i o n s and I s o l a t i o n w i t h i n the sp e c i e s i s not complete. Assuming t h a t a peak i n the abundance of a d u l t s i s an i n d i c a t i o n of the p e r i o d of bree d i n g , there i s a s t r o n g sug-g e s t i o n from the data t h a t the b r e e d i n g c y c l e s , f o r Calanus  g l a c i a l i s and C. p a c i f i c u s c a l i f o r n i c u s a re out of phase w i t h one another. There i s a p e r i o d pf o v e r l a p when the number of C; g l a c i a l i s a d u l t s i s d e c r e a s i n g and C. p. c a l i f o r n i c u s a d u l t s i n c r e a s i n g . T h i s p e r i o d occurs i n the e a r l y s p r i n g and i s ' t h e most important p e r i o d w i t h regard, t o i n t e r b r e e d i n g . F u r t h e r , i t appears as though C. p. c a l i f o r n i c u s may produce two broods d u r i n g the year, one i n l a t e s p r i n g - e a r l y summer and one i n l a t e summer. C. g l a c i a l i s on the other hand has onl y one br e e d i n g p e r i o d . i The y e a r l y c y c l e e x h i b i t e d by Calanus g l a c i a l i s i n I n d i a n Arm i s : not u n l i k e the p a t t e r n found, f o r Calanus i n more n o r t h -e r n waters. C. f i n m a r c h i c u s breeds only once a year i n west Greenland and Ungava Bay (Fontaine, 1955? M a c l e l l a n , 1967), but i n the warmer r e g i o n s of the Clyde Sea and E n g l i s h Channel t h i s s p e c i e s may produce s e v e r a l broods ( M a r s h a l l and Orr, 1955). Copepods of the A r c t i c and S u b - a r c t i c breed.and spawn so t h a t the young o f t e n appear a t the begin n i n g or a t the peak of phytoplankton blooms. Such peak p e r i o d s of primary pro-d u c t i o n are sudden and. over the year the r e l a t i v e time of h i g h primary p r o d u c t i v i t y i s s h o r t (Dunbar, 1968). O b v i o u s l y s u r v i v a l of second and t h i r d broods would be l e s s once the y e a r l y p e r i o d of h i g h p r o d u c t i v i t y had r e a c h e d , i t s peak, and the p a t t e r n o f t e n found i n such n o r t h e r n s p e c i e s i s a l i f e c y c l e t h a t may span a p e r i o d of one, two or more years (Dun-bar, 1968).' In I n d i a n Arm, C. g l a c l a l i s begins t o moult t o the a d u l t stage about a month b e f o r e the f i r s t phytoplankton bloom i s i n evidence. D u r i n g the two months i n which the c h l o r o p h y l l a n a lyses were taken i n t h i s survey, the develop-ment of the y e a r l y c y c l e of both s p e c i e s of Calanus was a l s o noted. I n February 1968, some c h l o r o p h y l l A was measured, but i n March 1968, the measurement of c h l o r o p h y l l A showed a marked i n c r e a s e over the p r e c e d i n g month. C. g l a c l a l i s had started, to moult i n January, i n February the number of a d u l t s had i n c r e a s e d n e a r l y 50% over the previous month, and. i n March the number of a d u l t s was a t i t s peak. About two months a f t e r the peak i n a d u l t s , , a peak occured. i n the S-:tage-V copepodites of C. g l a c l a l i s s u g g e s t i n g t h a t the time f o r egg m a t u r a t i o n and subsequent development f o r j u v e n i l e s i s not u n l i k e t h a t reported, f o r C. f i n m a r c h i c u s . I t i s c u r i o u s , however, t h a t C. g l a c i a l l s r e t a i n s a y e a r l y c y c l e p a t t e r n t y p i c a l of the A r c t i c and s u b - A r c t i c animals whereas popula-t i o n s of other s p e c i e s , i . e . , C. f i n m a r c h i c u s , appear t o have a . d i f f e r e n t y e a r l y c y c l e I n temperate than i n more n o r t h e r n c o o l e r waters. The males of Calanus g l a c i a l l s i n I n d i a n Arm a r e o n l y p r e s e n t f o r a s h o r t time. T h i s s p e c i e s i s considered r e p r e -s e n t a t i v e of A r c t i c and s u b - A r c t i c fauna (Jaschnov, 1955; Duhbar, 1968) and the males of Calanus appear t o be more sen-s i t i v e t o environmental changes than the females ( M a r s h a l l and Orr, 1955).. C o n c e i v a b l y then, the l a c k of a second brood i n t h i s s p e c i e s c o u l d be due t o the i n a b i l i t y of the males t o s u r v i v e the summer c o n d i t i o n s i n the i n l e t . A second p o s s i -b i l i t y i s based on Gause's'.^; pr i n c i p l e ; , and n a t u r a l . s e l e c t i o n . C. g l a c i a l i s breeds e a r l i e r than C. p. c a l i f o r n i c u s and, as a r e s u l t , animals a t a comparable stage of development are not present a t the same time. I f comparable stages of both s p e c i e s were present, c o m p e t i t i o n could r e s u l t i n the e x c l u s i o n or r e d u c t i o n i n number of one or the other s p e c i e s , but when com-pa r a b l e stages a r e not c o i n c i d e n t , c o m p e t i t i o n may be absent or reduced and. bot h s p e c i e s are a b l e t o ma i n t a i n b r e e d i n g p o p u l a t i o n s . The members of a s p e c i e s which breed a t a time when such c o m p e t i t i o n i s a t a minimum, are s e l e c t e d f o r s i n c e these are the i n d i v i d u a l s t h a t p e r s i s t and subsequently breed when proper environmental c o n d i t i o n s a g a i n p r e v a i l . Onset of moulting can be induced by i n c r e a s e d temperature and abundant foo d i n the l a b o r a t o r y . Stage-V copepodites, taken a t a time of the year when the m a j o r i t y of the popula-t i o n i s i n the o v e r w i n t e r i n g stage, w i l l s t a r t t o mbult, when food, organisms a r e pr e s e n t . T h i s occurs even a t low tempera-t u r e s ( 5 ° C). I n January 1968, however, gtage-V C. g l a c i a l i s moulted as w e l l without food as when food was added. S i n c e primary p r o d u c t i v i t y i n the environment was low d u r i n g t h i s month and. 5 ° C and 10° C experimental temperatures showed l i t t l e effect on moulting rate, i t would appear that some other factor or combination of factors is involved iniinducing moulting the adult stage i n this species. No such anomaly was noted for C. p. californicus. One possible factor that was not tested is the increasing length of day at this time of year. The ecological results show that the stage-V of C.  glaci a l i s occurs mainly in water below 100 meters depth, how-ever, and, i t seems unlikely that changes in length of light period has any real effect at this depth, particularly since this stage undergoes very l i t t l e vertical migration. The possibility of food acting as a stimulus should not be ruled out. L i t t l e i s known of the minimum amount needed to stimu-late moulting and. the amount of food, organisms present in January 1968 particularly with regard to flagellates and other smaller organisms was not determined. The lack of measurements in the preceding months as well makes i t d i f f i c u l t to determine i f any increase i n available food occurred. The slight or no change in the moulting rate of both forms between 10° and 15° C (Pig. 24) i s probably an indication of a minimal reaction time which an animal from the natural environment requires before moulting, i.e., the reaction to the experi-mental . temperature and, abundant food e l i c i t s a series of phys-iological changes which eventually result in moulting, but this process requires a minimal time period. Prom the results in Indian Arm, there is evidence to support the hypothesis that the two species occupy different bodies of water. The r e a c t i o n s of males, females and Stage-V copepodites w i t h i n the p o p u l a t i o n s of each s p e c i e s appear t o d i f f e r , p a r t i c u l a r l y i n C. g l a c i a l l s . Over the p e r i o d of study the three water bodies i n I n -d i a n Arm, d e f i n e d on the grounds of temperature and s a l i n i t y , appear t o be c o n s i s t e n t l y p r e s e n t . Calanus g l a c l a l i s Is p r i -m a r i l y a s s o c i a t e d w i t h the deep l a y e r , whereas C. p. c a l l f -o r n i c u s i s p r i m a r i l y found, i n the i n t e r m e d i a t e water. The deep l a y e r i s more uniform over the year w i t h r e s p e c t t o f l u c t u a t i o n s i n temperature and s a l i n i t y than-the i n t e r m e d i -a t e or s u r f a c e l a y e r s . T h i s may be an i n f l u e n t i a l f a c t o r i n d e t e r m i n i n g the v e r t i c a l p o s i t i o n of the two s p e c i e s and, i n f a c t , C. p. c a l l f o r n i c u s may be more t o l e r a n t of such f l u c -t u a t i o n s . The d i s t r i b u t i o n a l survey showed t h a t Calanus p a c i f i c u s  c a l l f o r n i c u s was more abundant i n waters of r e l a t i v e l y h i g h temperature and s a l i n i t y . I n I n d i a n Arm, however, the s a l i n -i t i e s are n o t i c e a b l y l e s s d i l u t e than those encountered any-where a l o n g the open coast and o n l y i n the summer do the tem-p e r a t u r e s approach c o n d i t i o n s comparable t o these found o f f C a l i f o r n i a . C. g l a c i a l l s occurs i n waters which are much c o o l e r than those found over the year i n I n d i a n Arm deep and i n t e r m e d i a t e water and, with regard, to s a l i n i t y , I n d i a n Arm i s more d i l u t e than the s u b - A r c t i c water w i t h which the s p e c i e s has been a s s o c i a t e d i n the open sea. D e s p i t e these d i f f e r -ences bo t h s p e c i e s are a b l e to s u r v i v e and reproduce i n I n d i a n Arm and a p r e f e r e n c e w i t h regard t o h a b i t a t i s e v i d e n t . On these grounds the c o n d i t i o n s which determine a s u i t a b l e h a b i -t a t f o r e i t h e r s p e c i e s Include more than temperature and s a l -i n i t y a l t h o u g h these f a c t o r s may be i n f l u e n t i a l when one or the o t h e r becomes l i m i t i n g . A - n o t i c e a b l e r e a c t i o n occurred i n May and June 1967. Dur-i n g t h i s time temperature and s a l i n i t y over the- water column was more uniform than a t any other time. The i n d i c a t i o n based on the f i n d i n g s of G i l m a r t l n (1962) was-that an o v e r t u r n had o c c u r r e d . T h i s i s the only p e r i o d when extreme v e r t i c a l m i g r a t i o n s were evidenced, p a r t i c u l a r l y i n the case of Stage-V C. g l a c l a l i s , and I f t h i s s p e c i e s i s normally a s s o c i a t e d w i t h water of a p a r t i c u l a r type the r e a c t i o n of t h i s stage may a l s o be evidence of such an o v e r t u r n . I n a l l the other sampling p e r i o d s the stage remained i n the deep l a y e r . V e r t i c a l communities have been d e s c r i b e d f o r the Gulf of Maine (Bigelow, 1926) so t h a t the o c c u r r e n c e - o f d i f f e r e n t a s s o c i a t i o n s of animals a t d i f f e r e n t depths i s not unique. S e g r e g a t i o n of males, females, and Stage-V's has been noted, f o r C. f i n m a r c h i c u s , and the b e h a v i o r w i t h r e s p e c t t o deep h a b i t a t and l a c k of v e r t i c a l m i g r a t i o n i s s i m i l a r t o t h a t found f o r C. g l a c i a l l s i n t h i s study ( N i c h o l l s , 1933). The males and Stage-V's occurred mainly i n the deep l a y e r and, w i t h the e x c e p t i o n of May 1967,: n e i t h e r of the two stages migrated e x t e n s i v e l y . The females on the other hand under-went a d e f i n i t e m i g r a t i o n In most sampling p e r i o d s except i n September 196? and January 1968. During the former p e r i o d most of the C. g l a c i a l i s population was i n the overwintering Stage-V and i n the l a t t e r period moulting to the adult stage was just beginning to occur. In both cases the t o t a l number of females i s less than that found at other times and a com-parison of migration patterns when r e l a t i v e l y low numbers are present may lead to f a l s e conclusions. The occurrence pf the main female population somewhat above the other two stages has been noted f o r C. finmarchicus (Nicholls,. 1933). In In-dian Arm, the female C. g l a c i a l i s usually appears i n the lower part of the intermediate layer. During the early months of the year when the C. g l a c i a l i s population i s beginning to moult, copulate, and spawn, t h i s v e r t i c a l displacement of the females i s puzzling. When females with spermatophores were t a l l i e d , however, i t was noticed that the bulk of the females with an attached spermatophore occurred somewhat be-low the main female population and was closer to or overlap-ped with the range of the males of the species. For C. f i n -marchicus around the B r i t i s h I s l e s , a period of one month elapses between moulting to adult and, maturation of the eggs (Marshall and Orr, 1955). Remembering the s i m i l a r i t i e s of the yearly cycle f o r l o c a l C. g l a c i a l i s and that described f o r C. finmarchicus, the female C. g l a c i a l i s i n Indian Arm that oocur above the males have probably been f e r t i l i z e d and are i n the process of maturing eggs. Those females occurring deeper usually bear spermatophores i n d i c a t i n g copulation i n the near past. They a l s o occur near the main p o p u l a t i o n of Stage-V copepodites of the s p e c i e s . These C. Z females are probably newly moulted, and soon a f t e r w a r d they are f e r t i -l i z e d by the males. A m i g r a t i o n upward then ensues w h i l e the eggs mature. S i n c e energy i s needed f o r egg p r o d u c t i o n and most of the primary p r o d u c t i v i t y takes p l a c e I n the upper layers,' t h i s upward, displacement of the females may have s i g -n i f i c a n c e i n terms of o b t a i n i n g energy f o r egg p r o d u c t i o n . Females maturing eggs a r e nearer a food source. A l s o i t has been shown t h a t egg l a y i n g c o i n c i d e s w i t h the occurrence of phytoplankton blooms (Dunbar, 1968) w i t h the s u p p o s i t i o n t h a t young are not produced u n t i l s u f f i c i e n t f o o d i s a v a i l a b l e f o r t h e i r s u r v i v a l . The a d u l t s can m a i n t a i n themselves on food r e s e r v e s b u i l t up d u r i n g the Stage-V c o n d i t i o n , but the young l a c k such r e s e r v e s a f t e r the y o l k has been used up. T h i s oc-curs about the t h i r d n a u p l i u s stage ( M a r s h a l l and Orr, 1955). A v e r t i c a l displacement of the females maturing eggs may be an i n d i c a t i o n of an environmental a d a p t a t i o n . Thus the young, when hatched, are c l o s e r t o the main f o o d source i n the water column and consequently have a g r e a t e r chance f o r s u r v i v a l than young hatched i n deep water, w e l l below the r e g i o n of maximum food supply. A t h i r d p o s s i b i l i t y e x p l a i n i n g t h i s up-ward movement of the female p o p u l a t i o n l i e s i n the f a c t t h a t an egg released, i n the upper o r s u r f a c e water takes l o n g e r t o s i n k and re a c h bottom than an egg r e l e a s e d i n deeper water. A p e r i o d of 24 hours i s r e q u i r e d f o r h a t c h i n g i n the eggs of C ; finmarchicus (Marshall and O r r , 1955). and. s u r v i v a l of an egg once i t becomes mired at the bottom i s d o u b t f u l ; thus the greater the distance an egg can s i n k before nearing bottom the greater the chances of s u r v i v a l of the nauplius upon hatching. i V e r t i c a l s e p a r a t i o n of males, females, and Stage-V's of C.i p a c i f i c u s c a l i f o r n i c u s i s not as evident, and contrary to C. g l a c i a l i s a l l three stages appear to migrate v e r t i c a l l y . There i s a good degree of overlap between males and females of t h i s species and since t h e y . l i v e i n or near to the r e g i o n of maximum primary p r o d u c t i v i t y a v e r t i c a l displacement of the females toward the upper l a y e r i s not necessary I f the foregoing hypothesis i s t r u e . • The presence of a food source i n the deep l a y e r has been confirmed by the c h l o r o p h y l l analyses and h o r i z o n t a l tows with f i n e mesh nets . Gut content analyses confirmed the presence of deep o c c u r r i n g food, organisms i n the animals. The food a v a i l a b l e may not be s u f f i c i e n t to s u s t a i n the younger stages s i n c e a sudden increase i n numbers of Calanus must occur i f each female releases a number of eggs. The n a u p l i i may not eat the same type of food as the a d u l t s , but the e a r l y cope-podite stages have o r a l appendages s i m i l a r to the Stage-V and. a d u l t s and have the p o t e n t i a l to compete w i t h the l a t e r stages f o r s i m i l a r food, organisms. As a r e s u l t the upward d i s p l a c e -ment of ovigerous females toward a more abundant food source may be an adaptation necessary to the s u r v i v a l of the s p e c i e s . Although both s p e c i e s are m o r p h o l o g i c a l l y s i m i l a r and appear t o be c l o s e l y r e l a t e d , t h e r e are a number of d i s t i n c t d i f f e r e n c e s not only i n e x t e r n a l morphology but i n t h e i r d i s -t r i b u t i o n and g e n e r a l ecology. I f they are t o be r e c o g n i z e d as d i s t i n c t s p e c i e s then two p o p u l a t i o n s such as"those of I n d i a n Arm must be r e p r o d u c t i v e l y i s o l a t e d . Many thousands of specimens of both s p e c i e s were examined i n t h i s study. Animals from v a r i o u s r e g i o n s and. from d i f f e r e n t times of year were s u b j e c t e d to d e t a i l e d m o r p h o l o g i c a l a n a l y -s i s , but a t no time was t h e r e an appearance of a form which could, be construed as b e i n g i n t e r m e d i a t e between Calanus. g l a c i a l l s and C. p a c i f i c u s c a l l f o r n i c u s . A p r i o r i i t would appear t h a t the two groups a r e r e p r o d u c t i v e l y i s o l a t e d , and. even though c o p u l a t i o n may occur between them development Is incomplete. The e c o l o g i c a l data from I n d i a n Arm shows the y e a r l y c y c l e s t o be d i f f e r e n t a l t h o u g h t h e r e i s a period, when i n t e r -b r e e d i n g could, occur. T h i s time i s u s u a l l y i n the l a t e w i n t e r - e a r l y s p r i n g d u r i n g which the p o p u l a t i o n of a d u l t C.  g l a c l a l i s i s waning and the p o p u l a t i o n of a d u l t C. p. c a l l f -o r n i c u s i s i n c r e a s i n g . When t h i s p a t t e r n was noticed, i n e a r l y 1967 a s e r i e s of 24 hour s t a t i o n s f o r e a r l y 1968 was scheduled so t h a t the d e t a i l e d r e a c t i o n s of the two popula-t i o n s d u r i n g t h i s c r i t i c a l time c o u l d be s t u d i e d . The v e r t i c a l d i s t r i b u t i o n s , p a r t i c u l a r l y over a 24 hour p e r i o d , show t h a t the p o t e n t i a l f o r b r e e d i n g between C. g l a -t cialls males and C. p. californicus females is very low. In general the C. glacialis males occupied the deep water whereas the C. p. californicus females were generally In the middle or upper part of the intermediate water. Over any one 24 hour period there was no real change in the relative positions of these males and females. On the other hand, overlap between C. glacialis females and C. p. californicus males occurs and is particularly evident in March 1968 over the 24 hour period. The overlap between these two typesaappears greatest about the time the female C. glacialis start to move upward in the water column presumably while maturing their,eggs. Supposed-ly these females have been fertilized while in the deep water with the male C. glacialis. but since l i t t l e . i s known about the frequency of copulation for any one Calanus female, the possibility for copulation with C. p. californicus males ap-pears to exist. The evidence provided by tallying the number of females with spermatophores supports the hypothesis that reproductive isolation is present. During March 1968, when the overlap be-tween C. glacialis females and C. p. californicus males was most evident, none of the former had. spermatophores attached but, in the population of C. p. californlcus.females present at this time, a distinct proportion were observed with sper-matophores. If Interbreeding were to occur to a significant degree, one would expect to find spermatophores on the C.  glacialis females since male C. glacialis decreased consider-a b l y i n abundance at t h i s time. During times when males of C. g l a c i a l l s a r e low or absent, i n number the occurrence of spermatophores on the females Is r a r e or absent a l l t o g e t h e r . T h i s same c o r r e l a t i o n has been noted f o r C. p. c a l l f o r n i c u s . I n February 1 9 6 8 t h e r e was some o v e r l a p over,a 2 4 hour period, between C. g l a c l a l i s females and C. p. c a l l f o r n i c u s males, but when the d i s t r i b u t i o n of G. g l a c i a l l s females w i t h a t t a c h -ed spermatophores was noted, they were found mainly below the m a j o r i t y of the C. p. c a l l f o r n i c u s males and overlapped s i g -n i f i c a n t l y w i t h male C. g l a c i a l l s . The o v e r l a p between males and. females over a 2 4 hour p e r i o d , f o r Calanus g l a c i a l l s , was g r e a t e s t i n January 1 9 6 8 , when the s p e c i e s began m o u l t i n g t o the a d u l t stage. I n Feb-r u a r y : the t o t a l number of a d u l t s of t h i s s p e c i e s increased, and the" p o p u l a t i o n of females s t a r t e d t o move upward so t h a t o v e r l a p w i t h the male p o p u l a t i o n l e s s e n e d . By March the num-ber of a d u l t s decreased, p a r t i c u l a r l y the male c o n t i n g e n t , and the female p o p u l a t i o n had. migrated upward t o the I n t e r -mediate l a y e r . I f both forms were t o behave as good s p e c i e s i n the sense employed, by Mayr ( 1 9 4 2 ) , then.gene flow between the two popu-l a t i o n s would be b l o c k e d . T h e - b l o c k i n g mechanisms are not a l -ways apparent i n p l a n k t o n i c s p e c i e s , p a r t i c u l a r l y s i n c e obvious g e o g r a p h i c a l b a r r i e r s and wide s e p a r a t i o n of r e p r o d u c i n g popu-l a t i o n s do not always e x i s t . Only through a thorough e c o l o g i c -a l a n a l y s i s can the taxonomic r e l a t i o n s h i p s between popula-t i o n s 6f s i m i l a r , c l o s e l y r e l a t e d organisms be c l a r i f i e d . The r e s u l t s of the f i e l d study i n I n d i a n Arm, B r i t i s h Colum-b i a , r e v e a l e d a d i f f e r e n t p a t t e r n of y e a r l y c y c l e s and v e r -t i c a l d i s t r i b u t i o n between the Large and Small Form of toothed Calanus. By v i r t u e of these d i f f e r e n t p a t t e r n s , t h e r e i s a s t r o n g i n d i c a t i o n t h a t i n t e r b r e e d i n g occurs o n l y a s m a l l per-centage of the time i f a t a l l , and on t h i s b a s i s , the Large and S m a l l Form appear t o behave more l i k e two separate and d i s t i n c t s p e c i e s than v a r i a n t s of one s p e c i e s . BIBLIOGRAPHY Aron, W. , E. H. Ahlstrom, B. McK. Bary, A. W. H. Be, and W. D. Clarke. 1965* Towing characteristics of plankton sampl-ing gear. Limn, and Ocean. 10(3): 333-340. Barnes, H . , and M. Barnes. 1953* Biometry of Calanus fin-marchicus in Stage V and VI. J. Mar. Biol. Ass., U.K. .22(2)1 305-313. Bary, B. McK. 1963. Temperature, salinity and plankton in the eastern North Atlantic and coastal waters of Britain, 1957. I* The characterization and distribution of surface waters. J. Fish. Res. Bd. Canada, 20(3): 789-826. 1964. Temperature, salinity and plankton in the eastern North Atlantic and Soastal waters of Britain, 1957. IV. The species' relationship to the water body: its role in distribution and in selecting and using indi-cator species. J. Fish. Res. Bd., Canada, 21(1): I 8 3 -202. Behrens, S. 1968. Some protein differences between two mor-phologically similar forms of the copepod genus Calanus (Crustacea: Calanoida), as indicated by starch gel electrophoresis. B.Sc.(Hons) Thesis, Univ. of British Columbia, Dept. Zool. Brodsky, K. A. 1948. Svobodnozhivushchie veslonogie rachki (Copepoda) Yaponskogo morya (Free-Living Copepod Crusta-ceans (Copepoda) of the Sea of Japan). Izvestiya Tkhookeanskogo Institua Rybnogo Khozyaistva i Oleano-grafi i , Vol. 26. 1950. Calanoida of the far eastern and polar seas of the U.S.S.R. Fauna of the U.S.S.R., J£i 1-442. Pub. Inst. Acad. Sci. Moscow. 1959. On the phylogenetic relationship of certain species of Calanus (Copepoda) from the northern and south-ern hemispheres. Zool Zhur. 3 8 ( 1 0 ) : 1537-1553. -— 1965. Variability and systematics of the species of the genus Calanus'(Copepoda). I. Calanus pacificus Brodsky, 1948 and C. sinicus Brodsky, sp. n. Acad. Nauk CCCP, Zool. Inst. Issledovaniya Fauni Morey III(XI) pp. 22-71. Caiman, W. T. 1909. Crustacea. In: A Treatise on Zoology (R. Lankester, ed.), Vol. 7. Part 3. pp. 1-346. Black, London. Cameron, F.E. 1957. Some f a c t o r s i n f l u e n c i n g the d i s t r i b u -t i o n of p e l a g i c copepods i n the Queen C h a r l o t t e I s l a n d s area. J . F i s h . Res. Bd. Canada, 14(2): 165-202. Campbell, M. H. 1929. Some free-swimming Copepods of the Vancouver I s l a n d r e g i o n . Trans. Roy. Soc. Canada, 23: 303-332. 1930. Some free-swimming Copepods of the Van-couver I s l a n d r e g i o n . I I . Trans. Roy. Soc. Canada, 24: 177-182. Chapman, -V>. J . 1962. The A l g a e . Macmillan & Co., L t d . , London. 472 pp. Cro s s , F. A. and L. F. S m a l l . 1967. Copepod i n d i c a t o r s of sur f a c e water movements o f f the Oregon coast. Limnol. and Ocean. 12(1): 60 - 7 2 . C u r r i e , M. E. 1918. E x u v i a t i o n and v a r i a t i o n of p l a n k t o n copepods with s p e c i a l r e f e r e n c e t o Calanus f i n m a r c h i c u s . Proc. Roy. Soc. Canada, S. 3, 12: 207-233. D a v i s , C. C. 1949. The p e l a g i c Copepoda of the N o r t h e a s t e r n P a c i f i c Ocean. Univ. of Washington Pub. i n B i o l o g y 14: 1-118. Digby, P. B. S. 1950. The b i o l o g y of some p l a n k t o n i c cope-pods a t Plymouth. J . Mar. B i o l . A s s , , U.K. 29_: 393-438. Dunbar, M.J. 1968. E c o l o g i c a l Development i n P o l a r Regions: A Study i n E v o l u t i o n . P r e n t i c e - H a l l Inc., Englewood C l i f f s , New J e r s e y . 119 pp. E s t e r l y , C. 0. I 9 0 5 . The p e l a g i c Copepoda of the San Diego Region. Univ. of C a l i f . P u b l . Z o o l . , 2(4): 113-233. 1924. Free-swimming Copepoda of San F r a n c i s c o Bay. Univ. of C a l i f . P u b l . Z o o l . , 26(5)1 81-129. Fleminger, A. 1964. D i s t r i b u t i o n a l A t l a s of C a l a n o i d Cope-pods i n the C a l i f o r n i a C u r rent Region, P a r t I. C a l i f o r n i a Cooperative Oceanic F i s h e r i e s I n v e s t i g a t i o n s . A t l a s no. 2 pp. 49 - 5 2 . F o n t a i n e , M. 1955« The p l a n k t o n i c copepods ( C a l a n o i d a , C y c l o -p o i d a , M o n s t r i l l o i d a ) of Ungava Bay, wi t h s p e c i a l r e f e r e n c e to the b i o l o g y of Pseudocalanus minutus and Calanus f i n -marchicus. J . F i s h . Res. Bd. Canada, 12(6): 859-898. F r o l a n d e r , H.E. 1 9 6 2 . Q u a n t i t a t i v e e s t i m a t i o n s of temperal v a r i a t i o n s of zooplankton o f f the coast of Washington and B r i t i s h Columbia. J . F i s h . Res. Bd. Canada, 1 9 ( 4 ) : 657-675. F u l t o n , J . I 9 6 8 . A l a b o r a t o r y Manual f o r the I d e n t i f i c a t i o n o f B r i t i s h Columbia Marine Zooplankton. T e c h n i c a l Re-p o r t No. 55, F i s h e r i e s Research Board of Canada, p. 33. G i l m a r t i n , M. 1962. Annual c y c l i c changes i n the p h y s i c a l oceanography of a B r i t i s h Columbia f j o r d . J . F i s h . Res. Bd. Canada, .12(5) * 9 2 1 - 9 7 4 . G r a i n g e r , E. H. I 9 6 I . The copepods Calanus g l a c i a l i s (Jasch-nov) and Calanus f i n m a r c h i c u s (Gunnerus) i n Canadian sub-a r c t i c waters. J . F i s h . ' R e s . Bd. Canada 1 8 ( 5 ) : 663-678. Heberer, G. 1 9 3 2 . Untersuchungen tlber Bau und Funktion der G e n i t a l o r g a n e der Copepoden. I. Der M&nnliche G e n i t a l -apparat der c a l a n c i d e n copepoden. Z e i t s c h r i f t f u r Mikro-skopischanatomische Forschung. _3JL: 2 5 0 - 4 2 4 . H e r l i n v e a u x , R. H. and J . P. T u l l y . I96I. Some oceanographic f e a t u r e s of Juan de Fuca S t r a i t . J . F i s h . Res. Bd. Canada, 1 8 ( 6 ) s 1 0 2 7 - 1 0 7 1 . Jaschnov, V. A. 1955* Morphology, d i s t r i b u t i o n and s y s t e m a t i c s of Calanus f i n m a r c h i c u s s. 1 . Z o o l . Zhur. j 4 ( 6 ) : 1 2 0 1 -1223. 1957. The P a c i f i c v a r i e t i e s of Calanus f i n m a r c h i -cus . s i 1 . Report of the P a c i f i c I n s t i t u t e f o r Marine and I c h t h y o l o g i c a l Economy and Oceanography. V o l . 4 4 . —. 1 9 5 8 . Comparative morphology of the s p e c i e s Calanus f i n m a r c h i c u s S. 1 . Z o o l . Zhur. j 6 ( 2 ) : 1 9 1 - 1 9 8 . 1 9 6 1 . Water masses and plankton. 1. S p e c i e s of Calanus f i n m a r c h i c u s s. 1. as i n d i c a t o r s of d e f i n i t e water masses. Z o o l . Zhur. 4 0 ( 9 ) : 1 3 1 4 - 1 3 3 4 . Lane, R. K. 1 9 6 2 . A review of the temperature and s a l i n i t y s t r u c t u r e s i n the approaches to Vancouver I s l a n d , B r i t i s h Columbia. J . F i s h . Res. Bd. Canada, 1 2 ( 1 ) : 45-91. L a B r a s s e r u , R. J . 1 9 6 4 . A p r e l i m i n a r y c h e c k l i s t o f some marine p l a n k t o n from the n o r t h e a s t e r n P a c i f i c Ocean. F i s h . Res. Bd. o f Canada, Manuscript Report S e r i e s (Ocean-ographic and l i m n o l o g i c a l ) No. 1 7 4 . Data Record. Legare, J. E. H. 1957. The qualitative and quantitative dis-tribution of plankton in the Strait of Georgia in relation to certain oceanographic factors. J. Fish. Res. Bd. , Canada, 14(4): 521-552. Maclellan, D. C. 1967. The annual cycle of certain Calanoid species in West Greenland. Can. J. Zool., 4^(1): 101-115. McMurrich, J. P. 1916. Notes on the plankton of the British Columbia coast. Trans. Roy. Soc. Can. Ser. 3, X(5)» 75-89. Marshall, S. M. and A. P. Orr, 1955. The Biology of a Marine Copepod. Oliver and Boyd, Edinburgh. 188 pp. Matthews, J. B. L. 1966. Experimental investigations of the systematic status of Calanus finmarchicus and C. glacialis (Crustacea: Copepoda! in! Some Contemporary Studies in .Marine Science. Pp. 479-492. Harold Barnes, ed. George Allen and Unwin Ltd. , London. Mayr, E. 1942. Systematics and the Origin of Species. Dover Pub. 1964. 334 pp. . Mullin, C. H. 1968. Egg-laying in the planlctonic copepod Calanus helgolandicus (Claus). Crustaceana, supplement No. 1, pp. 29-34. Park, Tai Soo. 1968. Calanoid Copepods from the central North Pacific Ocean. U. S. Fish and Wildlife Service Fishery Bulletin 6 6 ( 3 ) : 527-572. Raymont. J. E. I 9 6 3 . Plankton and Productivity in the Oceans. Macmillan Co., New York. 660 pp. Reid, J. L. i 9 6 0 . Oceanography of the northeastern Pacific Ocean during the last ten years. California Cooperative Oceanic Fisheries Investigations, Reports VII.. Pp. 77-90. Jan. I 9 6 0 . Reid, J. L . , G. I. Roden and J. G., ¥ y l l i e . 1958. Studies of the California Current System. California Cooperative Oceanic Fisheries Investigations. Progress Report 1 July 1956 - 1 January 1958. Pp. 27-56. Sars, G. 0 . I 9 0 3 . Art Account of the Crustacea of Norway. IV. Copepodai Calanoida. Bergen. Pp. 1-171. Shan, Kuo-cheng. 1962. Systematic and ecological studies on Copepoda in Indian Arm, British Columbia. M.Sc. Thesis, Univ. of B.C. Strickland, J. D. H. and T. R. Parsons. 1965. A Manual of Sea Water Analysis. Pish,. Res. Bd. Canada Bull . No. 125, 2d ed. Ottawa, 1965. Sverdrup, H. U. 19i+3- Oceanography for Meterologists. Pren-tice-Hall Inc. Pub. 2i|6 pp. Tullyj J. P. 191+2. Surface non-tidal currents In the ap-proaches to Juan de Fuca Strait. J. Pish. Res. Bd. Canada, 5(1+): 398-1-.09. Waterman, T. H. I960. The Physiology of Crustacea. 2 Vols. Academic Press, New York, London. 1315 pp. Wilson, C. G-. 191+2. The copepods of the plankton gathered ' during the last cruise of the Carnegie. Carnegie Cruise 7 (1928-1929), Biology Nos. 1-F^ 1950. Copepoda gathered by the United States Fisheries Steamer Albatross from 1887-1909, chiefly'in the Pacific Ocean. Bul l .„TJ . S. National Mus. 100(Vol. 111., Pt. k): 1J+1-W. With, C. 1915. .The Danish-Ingolf Expedition. Copepoda. I. Calanoida Amphascandria. Vol. III(li). PROCEDURE WITH STRATIFIED PLANKTON NET TOWS It is nearly impossible to tow a net horizontally at pre-cisely the same depth at which temperature and salinity measure-ments are taken. The region sampled by a net covers a range of depths in the vicinity of the region sampled hydrographically. This is due to the sin wave pattern followed by a net when being towed as a result of fluctuations in speed of the ship, tidal currents, wind, deep currents and possibly internal waves. •5 Also, Aron et al (1965) have shown that changes.in sampling depth are greater for equivalent fluctuations in towing speed (or wire angle) at slow towing speeds than they are at faster towing speeds, and greater fluctuations in sampling depth occur when the amount of wire out is increased. The diameter of the towing wire and the type of depressor or weight used are two ad-ditional factors which need to be considered when trying to maintain a consistent depth with a sampler (Aron et a l , I 9 6 5 ) . 17 ; • Since the opening and closing mechanisms of the Clarke-Bumpus nets fa i l to function efficiently at wire angles greater than 5 0 ° (about 2 . 5 knots with 5 0 lbs. of weight), slow speeds are a necessity. Trial tows using Kite-Otter and Isaacs-Kidd depres-sors proved to be unsuccessful in reducing the wire angle with increasing speeds, and lateral movement of the samplers became a problem. The diameter of the wire and the amount of weight at the end of the wire were kept constant throughout the sampl-ing program. 5/32 inch hydrographic wire and 5 0 lbs. of weight were used. Changes in weight of up to 200 lbs. appeared to have l i t t l e effect in reducing the fluctuation in wire angle with changes in towing speed. By adequate spacing of water bottles and thermometers, a relatively detailed description of temperature and salinity conditions over the water column may be determined. This helps to compensate for the fluctuation in net depth during a tow, and a reasonable estimate of temperature and salinity over the towing range can be made. Nets should be spaced on the wire in such a manner that depth ranges sampled by them do not overlap. The approximate towing speed and resultant wire angle must be anticipated to do this. Often a t r i a l run is advisable to es-tablish the proper ship speed and wire angle for the oceanic conditions prevalent at the time. In the inlets the commonest such oceanic conditions that may effect the wire angle are the tidal current, and wind with its effect on a ship towing at slow speeds. The majority of the ecological and distributional surveys were done with stratified tows. Clarke-Bumpus nets were spaced on the wire so that a 10° fluctuation in wire angle could be tolerated before depth ranges sampled by the nets would over-lap. The depth range sampled by a net at a particular position on the wire for a 10° wire angle change was determined from an angle chart. This chart (Fig. 1-1) was constructed with depths in meters on the vertical axis. Lines were drawn at 10° inter-vals with the origin at 0 meters. The lines for each interval were also scaled in meters. Figure 1-1. Wire Angle Chart. ANGLE CHART FOR ESTIMATI NG NET DEPTHS SCALE: 1cm =10m An arrangement such as this is based on the assumption that the wire behaves like a straight line during a tow. Rec-ords from the Bathykymograph indicate this is not the case. It is believed by other workers that the towing wire actually assumes a hyperbolic shape (Bary, personal communication). Further, these bathykymograph records show that the change in sampling depth for a concurrent change in wire angle is of a much smaller magnitude than one would predict from the angle chart. By using the angle chart to determine net spacing for avoidance of overlap in sampling range, one is actually over estimating the actual conditions and a margin of safety is introduced. To be absolutely certain of the depth of each net during a tow, a monitering device such as a time-depth recorder should be used. With one recorder placed by each net on the wire, a series of charts constructed from the recorder data would show the actual shape of the wire for various wire angles, and various amounts of wire out. Ideally, further observations made under various conditions of wind and tide would show the effect of these parameters. Unfortunately with the equipment available, this type of arrangement would interfere with the opening and closing messengers of the Clarke-Bumpus nets. In order to approximate the actual sampling depths, how-ever, a single time-depth recorder was placed immediately below the bottom net. During a tow the wire angle was monit-ered continuously, and the times when fluctuations in wire angle occurred were noted. Through t h i s procedure, w i t h a g i v e n amount of wire out, i t was p o s s i b l e to a s s o c i a t e par-t i c u l a r wire a n g l e s with p a r t i c u l a r depths. A working t a b l e was then c o n s t r u c t e d showing p o s i t i o n of the r e c o r d e r on the wire i n meters, wire angle, a c t u a l depth a t t a i n e d by the r e -cord e r f o r t h a t a n g l e , an e q u i v a l e n t s t r a i g h t l i n e a n g l e , and estimated sampling depths f o r nets p l a c e d a t known p o s i t i o n s above the r e c o r d e r . The e q u i v a l e n t s t r a i g h t l i n e angle i s a q u a n t i t y determined from the angle c h a r t . Reading down the v e r t i c a l a x i s of t h i s c h a r t to the depth determined by the r e c o r d e r f o r a p a r t i c u l a r measured wire a n g l e , the e q u i v a l e n t angle was d e f i n e d as the angle of the l i n e t h a t i n t e r s e c t e d with the recorded depth a t the p o s i t i o n o f the r e c o r d e r on the wire. F i g u r e 1-2 i s an example showing how e q u i v a l e n t s t r a i g h t l i n e a n g l e s were determined when the amount of wire out and angle of the towing wire were known. In t h i s case the bathy-kymograph was p l a c e d near the end of the towing wire w i t h 90 meters of wire out. The angle of the towing wire was 4-5° when the bathykymograph recorded a depth of 70 meters. Using t h i s i n f o r m a t i o n the e q u i v a l e n t s t r a i g h t l i n e angle was determined by r e a d i n g down the v e r t i c a l a x i s of the angle c h a r t t o 70 meters. Reading a c r o s s the c h a r t a l i n e was found such that the 90 meter p o i n t on i t s depth s c a l e i n t e r s e c t e d the 70 meter l i n e . The angle of t h i s l i n e from the v e r t i c a l a x i s was found to be 38°. T h i s value i s the e q u i v a l e n t s t r a i g h t l i n e a ngle. Sampling depths of nets p l a c e d above the r e c o r d e r may be estimated from t h i s l i n e , e.g., a n e t . p l a c e d a t 60 meters on For a g i v e n amount of wire out, a r e l a t i o n s h i p was estab-l i s h e d by p l o t t i n g measured wire angles a g a i n s t t h e i r e q u i v a l e n t s t r a i g h t l i n e a n g l e s . The r e s u l t i n g curves made i t p o s s i b l e to approximate the degree of f l u c t u a t i o n i n measured wire angle t h a t could be t o l e r a t e d f o r an e q u i v a l e n t f l u c t u a t i o n of 10° on the angle c h a r t (Table 1-1). F o r the range of a n g l e s encounter-ed on a tow, the e q u i v a l e n t angles were determined, and the sampling ranges of the nets estimated. T h i s estimate i s s t i l l based on the assumption t h a t the towing wire i s s t r a i g h t but only from the s h a l l o w e s t to the deepest net. For ease i n p l o t -t i n g , the median of the sampling range was con s i d e r e d the sampl-i n g depth. . Normally no more than f o u r Clarke-Bumpus n e t s were p l a c e d on the wire f o r any g i v e n tow. Each net had a counter t h a t monitered the number of r e v o l u t i o n s of an i m p e l l e r mounted i n the metal c o l l a r of the net frame. When t h i s device was c a l -i b r a t e d by towing the nets over a measured d i s t a n c e the number of c u b i c meters of water f i l t e r e d per r e v o l u t i o n o f the i m p e l l -e r was determined. By r e c o r d i n g the number of r e v o l u t i o n s of t h i s i m p e l l e r f o r each tow, the amount of water f i l t e r e d i n cubic meters was determined, and subsequently the number of pla n k t o n specimens per cu b i c meter estimated. F i g u r e 1-2. Example showing the d e t e r m i n a t i o n o f an e q u i v a l e n t s t r a i g h t l i n e a ngle. 80-TABLE 1-1 DETERMINATION OF EQUIVALENT WIRE ANGLES IN 10° RANGES TOTAL WIRE OUT =.90 meters RANGE- OF MEASURED WIRE ANGLE 20° to 37° 38° to 45° 46° to 60° TOTAL WIRE OUT = 200 meters RANGE OF MEASURED WIRE ANGLE 20° to 42° 42° to 55° 56° to 60° RANGE OF EQUIVALENT ANGLES' 20° to 30° 30° to 40° 40° to 50° RANGE OF EQUIVALENT ANGLES 20° to 30° 30° to 40° 40° to 50° THE EXTERNAL MORPHOLOGY OF THE TOOTHED CALANUS SPP. ' FROM THE WATERS OF SOUTHERN BRITISH COLUMBIA, CANADA ORDER. Copepoda Crustacea with head, thorax and abdomen. Head' of s i x co-a l e s c e d somites, rounded a n t e r i o r l y or with rostrum, without carapace, w i t h median n a u p l i a r eye but without compound eye. Thorax composed of a t l e a s t 7 somites some of which are n o t -fused; each u s u a l l y with 1. p a i r of appendages. F i r s t appendage p a i r m o d i f i e d to form m a x i l l i p e d s , l a s t 1 or 2 p a i r s o f t e n r e -duced or absent, remaining p a i r s biramous and n a t a t o r y . Abdo-men with maximum of k segments, devoid of appendages. T e l s o n w i t h 1 p a i r of caudal rami. D i v i s i o n p r e s e n t between f i f t h and s i x t h , or s i x t h and seventh t h o r a c i c somites d i s t i n c t , d i v i d i n g body i n t o a n t e r i o r prosome and p o s t e r i o r urosome. (Prosome composed of head and most o f thorax. Urosome composed of l a s t 1 or 2 t h o r a c i c somites and abdomen.) Antennules uniramous, u s u a l l y conspicuous. Antennae o f t e n biramous, o f t e n p r e h e n s i l e . Mandibles f r e q u e n t l y w i t h biramous or uniramous p a l p . M a x i l l a e w i t h opening of m a x i l l a r y gland a t base. M a x i l l i p e d s f r e q u e n t l y p r e h e n s i l e . F i f t h p a i r of t h o r a c i c l e g s f r e q u e n t l y m o d i f i e d f o r sperm t r a n s f e r i n male. Large copepods with oval body, urosome about 1/3 the length of prosome. Head or anterior-most tagma well defined or coalescent with f irst pedigerous segment; 2 rostral filaments present anteroventrally. Fourth and fifth pedigerous segments rarely fused. Lat-eral posterior conners of fifth pedigerous segment often rounded. Urosome 5-segmented in male; generally 4-segmented in female. Caudal rami with 6 setae. Antennules long, 16-25 segments in female, 15""24 segments in amel. Often thickened proximally in male, some proximal articulations fused, covered with setae and aesthetascs. An-tepenultimate and penultimate segments with 1 strong plumose seta posteriorly. Antennae biramous, rami nearly equal in length. A l l 5 pairs of legs generally natatory with three segment-ed exopodites and endopodites. First 2 anterior pairs sometimes with 1 or 2 segmented endopodites; fifth pair of legs in female same as preceding pairs, or in various stages of degeneration. Fifth pair in male often modified, asymmetrical, prehensile. Coxopodites of fifth legs smooth or denticulate on inner surface. Cephalosome fused with or distinct from thorax, fourth and fifth pedigerous segments never fused. Anterior end often slightly carinated dorsally, particularly in male. Urosome 4-segmented in female with genital segment slight-ly protuberant ventrally; 5-segmented in male. Caudal rami symmetrical with second seta from inner surface longest. Antennules 25-segmented in female, f irst 2 segments often fused in male; generally longer than body in both sexes. In males seta on antepenultimate segment noticeably shorter than seta on penultimate segment. Antennae with 7-segmented exopodite nearly equal in length to 2-segmented endopodite. Thoracic legs natatory, exopodites and endopodites 3-segmented. Exopodites of f irst 4 pairs of 1, 1, and 2 spines on outer surface of respective segments; terminal segment with apical spine. Endopodite of f irst pair with 1, 2 and 6 setae, respectively. Terminal segment of endopodites of second and third legs with 8 setae, those of fourth legs with 7 setae. Coxopodite of f irst 4 legs usually with stout plumose seta on inner surface. In females fifth legs similar to preceding pairs. In males fifth legs slightly asymmetrical, left exopodite longer; both exopodites without setae. Inner surface of coxopodite denticu-late or with solitary seta. SMALL FORM. Calanus sp. (Shan, 1962) Prosome (plate I) 2-parted, cephalothorax forming anterior part, 5 free thoracic somites forming posterior part. Cephalo-thorax consisting of head and f irst thoracic somite (Marshall & Orr, 1955). Anterior surface of head slightly protuberant. Ros-tral filaments present, situated anterior to anterinule. Small solitary hair-like processes present on anterior surface of head. Posterior dorsal surface of cephalothorax protuberant slightly at line of division with f irst pedigerous somite. First pedigerous somite between 1/3 and 1/2 the length of cephalothorax. Pedigerous somites 1 through 5 decreasing in length and width posteriorly. First pedigerous somite form-ing widest part of prosome, anterior edge slightly wider than posterior edge of cephalothorax. Lateral surface of third pedigerous somite with 2 setules, 1 near division with second pedigerous somite, second near divi-sion with four pedigerous somite. Fourth pedigerous somite with 1 setule laterally, near division with fifth pedigerous somite. Posterior lateral surface of fifth pedigerous somite ex-tending posteriorly to shield anterior lateral portion of genital segment. Posterior lateral margin of fifth pedigerous somite roundedi dorsal and ventral surface U-shaped not extend-ing over junction with genital segment. Urosome (plate I) four-segmented with 2 caudal rami. First, or g e n i t a l segment, l o n g e s t and widest, with 2 conspicuous spermathecae. V e n t r a l s u r f a c e p a r a l l e l to main a x i s of uro-some a t r e g i o n of g e n i t a l pore. S u c c e s s i v e urosome segments s h o r t e r and narrower p o s t e r -i o r l y } segments 3 and 4 of n e a r l y i d e n t i c a l l e n g t h . Caudal rami l o n g e r than wide, each with 4 t e r m i n a l plumose setaet second s e t a from i n n e r s u r f a c e l o n g e s t . 1 s u b - t e r m i n a l plumose seta on outer s u r f a c e , 1 s u b - t e r m i n a l plumose s e t u l e on i n n e r s u r f a c e . Antennule ( p l a t e I I ) . 25 segmented, f i r s t and second no-t i c e a b l y l a r g e r . Segments 3 to 9 n e a r l y equal i n l e n g t h , width d e c r e a s i n g s l i g h t l y w i t h each s u c c e s s i v e segment. Segments 10 and 11 s l i g h t l y l o n g e r than 1 - 9* Segments 12 to 25 markedly l o n g e r than wide; width of each segment d e c r e a s i n g s l i g h t l y . Segments 15 to 19 n e a r l y equal i n l e n g t h . Segments 20 and 21 of n e a r l y equal l e n g t h , but s l i g h t l y s h o r t e r than segments 15 to 19. Segment 22 with plumose s e t u l e on p o s t e r i o r s u r f a c e . Seg-ments 23 and 24 each wi t h s i n g l e l o n g plumose seta on p o s t e r i o r s u r f a c e , setae of equal l e n g t h . Segment 25 w i t h sub-terminal s e t a on a n t e r i o r s u r f a c e and 4 t e r m i n a l s e t a e . Antenna ( p l a t e I I I ) . Biramous, p r o t o p o d i t e 2-segmented, b a s i s l a r g e r than coxa. Exopodite 7-segmented, endopodite 2-segmented. Two setae on a n t e r i o r edge of b a s i p o d i t e . One plumose seta on coxa. F i r s t 2 segments of exopodite each with 2 l o n g plumose setae on ou t e r s u r f a c e . F i r s t segment wider than l o n g , l o n g e r on s i d e n e a r e s t endopodite. Second segment s l i g h t l y l o n g e r than wide; some specimens with length and width equal. Seg-ments 3» 4 , 5. and 6 shortest} each with 1 plumose seta on outer surface. Width of ramus decreasing to segment 5s segment 6 slightly wider and proximal end of segment 7 nearly as wide as distal end of segment 2. Segment 7 tapers toward distal end. This segment with one plumose seta on middle of outer surface, 3 plumose setae on terminus. Endopodite 2-segmented, proximal segment nearly as long v as exopodite. Outer sui-face with 2 plumose setae near distal end. Shorter terminal segment bilobed, outer lobe with 5 large plumose setae, 3 smaller plumose setae on outermost surface, and 1 small seta at base of inner edge. Inner lobe with 6 large plumose setae, and 1 small setule nearer inner surface. Mandible (plate I V ) . Biramous, protopodite 2-segmehted. Coxopodite longer than basipodite and endopodite combined. Segment nearly perpendicular to remainder of appendages toothed edge overlies labrum. Posterior corner of toothed edge with conspicuous tooth or spine. Lateral surface with 1 short plumose setule proximally. Basipodite irregular; inner edge longer than outer, with 3 setae on protuberance about 1/3 the length from articulation with endopodite, a fourth seta near mid-point of inner surface. Endopodite 1-segmented, slightly longer than half the length of basipodite. Protuberance on lateral surface with 4 setae, 10-plumose setae on terminus. Exopodite 5-segmented. Four proximal segments with one plumose seta, terminal with 2 plumose setae. M a x i l l u l e ( p l a t e I V ) . Gnathobase with 13 s h o r t plumose setae, on i n n e r s u r f a c e ; 1 s h o r t s e t u l e on a n t e r i o r s u r f a c e . F i r s t e x i t e w i t h 7 plumose setae on terminus, 2 plumose setae n e a r e r base. F i r s t e n d i t e much s m a l l e r than f i r s t e x i t e , l o b e l i k e , w i t h 4 plumose setae on terminus. Second e x i t e s m a l l , o f t e n hidden by f i r s t e x i t e i n mounted specimens, w i t h 1 plumose seta on terminus. Second e n d i t e ( f i r s t lobe of b a s i p o d i t e ) with 4 plumose setae on d i s t a l end, shape s i m i l a r t o f i r s t e n d i t e . Second l o b e of b a s i p o d i t e appears as protuberance near base of endopodite. D i s t a l s u r f a c e with 4 plumose setae. F i r s t l obe of endopodite appears as a lobe d i s t a l to sec-ond lobe of b a s i p o d i t e , with 4 plumose setae on terminus. Second l o b e of endopodite w i t h 2 groups of plumose setae. One w i t h k plumose setae d i s t a l to f i r s t l o b e , other on d i s t a l end w i t h 7 plumose setae. Exopodite a curved segment a r i s i n g between second e x i t e and base of endopodite, segment b e a r i n g 11 plumose setae. M a x i l l a ( p l a t e V, f i g . 3 ) . - Three-segmented. Proximal segment with 6 plumose setae grouped on i n n e r s u r f a c e d i s t a l l y . Second segment with 3 groups of 3 plumose setae each on l o b e -l i k e s t r u c t u r e s on inner; s u r f a c e . One plumose seta on outer s u r f a c e near proximal segment. D i s t a l segment with 4 setae on l o b e - l i k e s t r u c t u r e on i n n e r s u r f a c e , 1 s e t u l e near base of l o b e , 6 plumose setae i n s u c c e s s i o n to terminus d i s t a l to l o b e , 2 plumose setae sub-terminal i n c e n t e r of a n t e r i o r sur-f a c e . Maxilliped (plate V, fig. C). Eight-segmented. Proximal segment largest, with 3 groups of plumose setae, most proximal group with 3 other 2 groups with 4 setae each. Second protopodite segment with 3 plumose setae grouped in center of inner surface. Third segment smallest, with 2 plumose setae on inner surface near distal articulation of second protopodite segment. Fourth segment with 4 plumose setae grouped on small lohe in middle of segment near inner surface. Fifth and sixth segments nearly identical. Fifth with 4 plumose setae in group near distal articulation in inner sur-face. Sixth segment with 3 plumose setae in comparable posi- " tion. Seventh segment with one plumose seta on outer surface near proximal articulation, with 3 plumose setae on inner sur-face near distal articulation. Eighth segment with 3 plumose setae on terminus, with 1 sub-terminal plumose seta on outer surface. Anterior or f irst pair of swimming legs on second thoracic somite (plate VI, figs. A & B). Coxopodite with one plumose seta on inner surface. Basipodite with one curved plumose seta on anterior surface, adjacent to articulation with endopodite. Endopodite 3-segmented, shorter than exopoditej proximal seg-ment widest, with one plumose seta on inner surface. Second segment with 2 plumose setae on inner surface. Terminal seg-ment longest with 3 plumose setae on inner surface. . Exopodite 3-segmented. Proximal segment with one seta on inner surface» one spine on outer surface adjacent to a r t i c u l a ° tion with second segment. Second segment similar to proximal segment but smaller. Distal segment.with 3 plumose setae on inner surface, one sub-terminal plumose seta, one terminal plumose seta plus one seta-like spine.^ Terminal seta with membrane along outer surface, plumosities along inner surface.1 Terminal segment also with seta-like spine on outer surface 1/3 length from terminus. As with endopodite, proximal segment of exopodite broadest while terminal segment longest. Second pair of swimming legs symmetrical} on third thoracic somite (plate VII, figs. A & E). Coxopodite largest with one plumose seta on inner surface, and plumosities extending from seta to interpodal plate. Basipodite with no setae, but with spine on outer surface adjacent to articulation with exopodite. Endopodite 3-segmented; basal segment with one plumose seta on inner surface, distal outer surface drawn off to spine-like point. Second segment with 2 plumose setae on inner sur-face; outer surface drawn off to spine-like point near articu-lation with terminal segment. Terminal segment with 4 plumose setae on inner surface, 2 plumose setae on terminus, and 2 plumose setae on outer surface. Outer surface of second and 1. See discussion under description of exopodite of f irst swimming legs for Calanus pacificus californicus males. Exopodite 3-segmented, proximal segment wi t h one plumose seta on i n n e r s u r f a c e , spine on outer s u r f a c e , both a d j a c e n t t o a r t i c u l a t i o n with second segment. Proximal segment a l s o w i t h 2 " f l a p " on ou t e r d i s t a l s u r f a c e c o v e r i n g p a r t of a r t i c u l a t i o n . Second segment wi t h one plumose seta on i n n e r s u r f a c e near a r t i c u l a t i o n with t e r m i n a l segment. Spine and " f l a p " occur a d j a c e n t to d i s t a l a r t i c u l a t i o n . D i s t a l segment with 5 plumose setae on i n n e r s u r f a c e , one l o n g and one s h o r t spine on termin-us, one s h o r t spine 1 / 3 l e n g t h from terminus. T h i r d p a i r o f swimming l e g s on f o u r t h t h o r a c i c somite; e s s e n t i a l l y same as second p a i r but l o n g e r ( p l a t e V I I , f i g s . B & F ) . Fo u r t h p a i r of swimming l e g s on f i f t h t h o r a c i c somite; s l i g h t l y l o n g e r than t h i r d p a i r ( p l a t e V I I I , f i g s . A & C). Coxopodite l o n g e s t segment wi t h one plumose seta on i n n e r sur-f a c e . B a s i p o d i t e n e a r l y as l o n g as wide, with.no set a e . Short spine on ou t e r s u r f a c e near a r t i c u l a t i o n with exopodite. Be-tween a r t i c u l a t i o n w i t h exopodite and a r t i c u l a t i o n with endo-p o d i t e on a n t e r i o r d i s t a l s u r f a c e , a conspicuous s p i n e - i i k e e x t e n s i o n p r e s e n t . D i s t a l p o s t e r i o r s u r f a c e appears to o v e r l a p w i t h exopodite. Endopodite 3-segmented. Proximal segment s h o r t e s t / s e c o n d segment about twice as l o n g , and d i s t a l segment about f o u r times as l o n g . Proximal segment as i n second and t h i r d l e g s . 2. These " f l a p s " appear to be e x t e n s i o n s o f the more proximal of two a d j a c e n t segments. They may be membranous i n nature. D i s t a l segment with 3 plumose setae on i n n e r s u r f a c e , 2 term-i n a l setae, and 2 setae on outer s u r f a c e ; segment d i f f e r s from second and t h i r d l e g s i n t h i s a s p e c t . Exopodite 3-segmented. Pr o x i m a l segment s h o r t e s t , w i t h second and t h i r d segments p r o g r e s s i v e l y l o n g e r . T h i s ramus i d e n t i c a l to exopodites of second and t h i r d swimming l e g s . F i f t h p a i r of swimming l e g s on s i x t h t h o r a c i c somite ( p l a t e I X ) . Legs symmetrical, s h o r t e r than t h i r d or f o u r t h l e g s . Coxopodite with a row of t e e t h on i n n e r s u r f a c e ; t h i s row s l i g h t l y concave near middle of segment. B a s i p o d i t e s i m i l a r to f o u r t h swimming l e g . S p i n e ^ l i k e e x t e n s i o n on a n t e r i o r d i s t a l s u r f a c e near a r t i c u l a t i o n w i t h endopod p a r t i c u l a r l y e v i d e n t . Endopodite 3-segmented. Proximal segment s m a l l e s t , second segment s l i g h t l y l o n g e r , d i s t a l segment about 2.5 times as l o n g as p r o x i m a l . D i s t a l segment p r o p o r t i o n a t e l y not as l o n g as d i s t a l segment of endopodite of f o u r t h l e g . Segments 1 and 2 each with one plumose seta on i n n e r s u r f a c e . D i s t a l ( t h i r d ) segments wi t h 2 plumose setae on i n n e r s u r f a c e , one sub-terminal and one t e r m i n a l plumose seta on d i s t a l end; one smal l plumose se t a on outer s u r f a c e about 1/3 l e n g t h from t i p ; some specimens with a d d i t i o n a l plumose seta on outer s u r f a c e . One s h o r t t o o t h -l i k e spine j u s t l a t e r a l to d i s t a l m o s t t e r m i n a l s e t a . Exopodite 3-segmented. Proximal segment as i n second l e g ; but with no s e t a e . Second segment n e a r l y equal i n l e n g t h to prox i m a l segment, s i m i l a r to corres p o n d i n g segment of second leg. Distal segment with 4 setae on inner surface, one long spine and one short spine on terminus with short spine outside long spine. Outer surface, with short spine about 1/3 length from terminus. Longest terminal spine on exopodite of legs 2 through 5 with membrane-like structure along outer surface. Inner sur-face with fine plumosities. MALE. • Prosome (plate XI, fig. A) 2-parted as in female. Anter-ior surface of cephalothorax markedly protuberant, with small protuberance neai-ly opposite antennules on dorsal surface, and posterior dorsal surface produced markedly at point of division with f irst free thoracic somite. First free thoracic somite about 1/3 length of cephalothorax. Remainder of prosome as for small female. Urosome 5-segmented with 2 caudal rami. First segment peduncular with proximal end noticeably narrower than distal end. Articulation of f irst segment shielded laterally by posterior extensions of sixth thoracic segment. Second seg-ment longest. Width of distal end of first segment and width of second segment nearly equal. Successive segments narrower and shorter. Caudal rami' nearly equal in length to third seg-ment. Setae on caudal rami identical to small female. Antennule (plate XI, fig. A) 24-segmented. Proximal or first, segment largest, conspicuous macroscopically. Second segment markedly smaller, slightly angular on anterior surface, with conspicuous setule near distal articulation. Segments 2 to 8 wider than long; each succeeding segment from proximal to distal tapered in appearance. Segments 9 and 10 nearly as wide as long. Segments 11 to 24 markedly longer than wide. Segments 12 to 18 of nearly equal length,but decreasing width thus tapered in appearance. Segments 19 to 22 a l l nearly equal in length, but slightly shorter than segments 12 to 18. Segments 2 3 and 24 nearly equal in length but shorter than segments 11 to 22 . Segment 21 with setule on posterior surface near ar-ticulation with segment 22. 2 large conspicuous setae on pos-terior surface of segments 22 and 23; seta on segment 22 (ante-penultimate segment) longer. Terminal segment with 4 setae and aesthetasc on distal end. Sub-terminal setule on anterior surface. Male antennule with many more aesthetascs on outer or anterior surface than female antennule. Antenna (plate XII, fig. B), biramous, protopodite 2-seg-mented, basis with conspicuous, plumose seta. Coxa larger and orbiculate, with 2 plumose setae on anterior surface near ar-ticulation with endopodite. Endopodite 2-segmented, exopodite 7-segmented. Exopodite similar to small female except second segment slightly longer than wide. Endopodite same as description for small female. Mandible (plate XIII, f ig. B) similar in appearance to small female. Gnathobase of. coxopodite conspicuously dentate. Basipodite same as small female. Endopodite same as small female. Exopodite same as small female. Maxillule (plate XIV, fig. C) same as description for small female. Maxilla (plate XIV, figs. D & E) same as description for small female. Maxilliped (plate XV, fig. A) as in small female except seta on outer surface of seventh segment larger in male and re-flexed toward proximal end of appendage. Sub-terminal seta on outer surface of eighth or terminal segment also larger than in female and reflexed toward proximal end of appendage. Anterior or f irst pair of swimming legs on second thoracic somite (first free thoracic somite), and symmetrical (plate XVI, f ig. A). Coxopodite largest segment with plumose seta on inner surface. Basipodite slightly wider than long, with curved plumose seta on anterior surface adjacent to articulation of endopo-dite. Segment shorter on lateral side. Endopodite. First or proximal segment nearly as wide as long, 1 plumose seta on inner surface. Second segment small-est, with 2 plumose setae on inner surface. Third or distal segment longest, with 3 plumose setae on inner surface, 2 plumose setae on terminus, and one plumose seta on outer sur-face about 2/3 of length from proximal end of segment. End of Exopodite. First or proximal segment broadest. Spine lateral to articulation with second segment. Inner surface with p lumos i t ie s» distinctly rounded from proximal end to point of attachment of seta. Second segment shorter than f irst , not rounded, but with spine lateral to distal articulation, and with plumose seta on inner surface near distal articulation. Inner surface with plumosities. Distal segment longest, inner-surface with 3 plumose setae, terminus with one sub-terminal and one terminal plumose seta. Terminal seta with membrane structure as in small female. Outer surface with 1 seta-like spine near terminus and second seta-like spine about 2/3 of length from proximal articulation. (These seta-like spines are thick at their bases like spines, but tips taper as a tip of a setule.. They appear devoid of plumosities.) Second pair of swimming legs with coxopodite as in small female (plate XVII, fig. A). Basipodite wider than long with spine on outer surface adjacent to articulation with exopodite. Endopodite 3-segmented, basal segment smallest, segments length-ening distally. Outer surface of f irst 2 segments drawn off to a spine-like point lateral to distal articulations. First segment with one plumose seta on inner surface. Second segment with 2 plumose setae on inner surface. Terminal segment with 4 plumose setae on inner surface; one sub-terminal and one term-inal plumose seta, 2 plumose setae on outer surface. Exopodite 3-segmented, f irst with "flap" near outer sur-face of distal articulation just medial to lateral spine. (See description for small female.) Inner surface with plumosities, and one plumose seta. Segment rounded on inner surface with broadest region near distal end at base of seta, narrowest region at proximal end. Second segment similar to f irst or proximal segment, but more rhomboidal in shape. Proximal por-tion of inner and outer surface with plumosities. Distal seg-ment longest, with 5 plumose setae on inner surface, 2 term-inal spines, inner one longer and with membrane as described for small female; with a tooth-like projection between bases of these 2 spines. One spine on outer surface about 2/3 of length from proximal articulation. Pores evident near base of short terminal spine and spine on outer surface. Third pore sometimes noticeable about mid-way between proximal articula-tion and base of spine on outer surface. Third swimming legs (plate XVII, fig. BO similar to sec-ond but larger. Fourth pair of swimming legs (plate XVII, fig.. C). Coxo-podite nearly twice as long as wide, with plumose seta as in small'female. Basipodite wider than lorig; distal outer sur-face drawn off to short spine-like process but no distinct spine as in second and third legs. Spinose process on anterior distal surface evident as in small female. Endopodite with plumosities on outer surface of proximal and second segments arid proximal portion of distal segment. Plumosities also on proximal inner surface of second and dis-tal segments. Distal segment with 3 plumose setae on inner surface, one sub-terminal and one terminal plumose seta, and \ 2 plumose setae on outer surface. Endopodite like endopodite of second leg in a l l other aspects. Exopodite. Inner surface of proximal segment not rounded as in second and third legs. Distal segment as in second leg. Plumosities on proximal outer surface of second and distal segments and along entire inner surface of proximal segment and proximal portion of second and third segments. Fifth swimming legs (plate XIX, fig. A). Asymmetrical, left leg longer than right. Inner surface of both with row of teeth, concave near middle of coxopodite; row extends away from inner surface onto posterior surface of segment. Basipodite with inner surface longer than outer in both legs. Inner surface curved, outer surface straight. Distal anterior articulation surface adjacent to exopod with conspicu-ous spinose process. Outer surface, lateral to distal articu-lation, drawn off to small spine-like process. Endopodite. Segments increase in length from first or proximal to third or distal. First segment sub-triangular with proximal end much narrower than distal. Outer surface of both f irst and second segments drawn off to spine-like process distally. First and second segments each with one plumose seta on inner surface. Distal segment with 2 plumose setae on inner surface and 2 on outer surface. Sub-terminal plumose seta medi-ally; terminal plumose seta, plus terminal, spinose process lateral to i t . Plumosities along inner and outer surfaces of second segment, and along proximal portion of corresponding sur-faces, of ^distal usegment^  •. Left exopodite longer than right. Segments decreasing in length from proximal to distal. Proximal segment with "flap" and spine lateral to distal articulation. Small pore on anterior surface just proximal to this spine. Second seg-ment shorter and narrower, with plumosities on inner surface. This segment with spine, "flap," and pore as in f irst segment. Distal segment oblong and shortest, Jwith short spine on outer surface about 2/3 length from base. Terminus with one short spine just latei-al to second slightly longer spine; also with small spinose process on anterior surface between these two spines. Plumosities along inner surface. Right exopodite with f irst 2 segments longer on outer surface. Both segments with flap-like process and spine as above, but both much shorter than corresponding segments on left exopodite. Shape like f irst 2 segments on exopodite of fourth swimming leg. Pores as in left exopodite. Plumosities proximally on outer surfaces of second and distal segments, along inner surfaces of segment 2 and proximally on inner sur-face of distal segment. Distal segment with spine on outer surface 2/3 length from proximal articulations one pore slightly more proximal to this spine. Terminus with 2 spines, outer-most shorter; short spinose process between these two. Longer of 2 terminal spines without membrane structure. Right exopodite slightly shorter than first 2 segments of left exopodite. First 2 segments of right exopodite slightly longer than first segment of left exopodite. LARGE FORM: Calanus sp. (Shan, 1962) FEMALE. Prosome ( p l a t e I, f i g . B) same as Small female except a n t e r i o r and w e l l rounded, mid-dorsal p o s t e r i o r margin of cephalothorax a t p o i n t of d i v i s i o n w i t h second t h o r a c i c somite not produced as i n Small female. Urosome ( p l a t e I , f i g . B) with f i r s t segment l o n g e r than wide; more so than Small female. D e s c r i p t i o n f o r Small female same f o r Large female. Antennule ( p l a t e I I , f i g . A ) . Same as d e s c r i p t i o n f o r Small female. Both females with p a r t i a l f u s i o n between seg-ments 8 and 9« Antenna ( p l a t e I I I , f i g . A) with p r o t o p o d i t e as i n Small female. Exopodite with second segment s l i g h t l y wider than l o n g thus d i f f e r s s l i g h t l y from Small female. Remainder of ramus i d e n t i c a l to d e s c r i p t i o n f o r Small female. Endopodite same i n appearance as Small female. Mandible ( p l a t e IV, f i g . B) same as Small female. M a x i l l u l e ( p l a t e IV, f i g . D) same as Small female. M a x i l l a ( p l a t e V, f i g . A) same as Small female, except f o r a d d i t i o n a l s e t u l e on t h i r d or t e r m i n a l segment of appendage. T h i s s e t u l e near proximal end of segment near s i t e of s e t u l e d e s c r i b e d f o r Small female. M a x i l l i p e d ( p l a t e V, f i g . E) same i n appearance as Small female. F i r s t p a i r of swimming l e g s ( p l a t e VI, f i g . C) same as Small female. Second p a i r of swimming l e g s ( p l a t e V I I , f i g . C) same as sm a l l female. T h i r d p a i r ( p l a t e V I I , f i g . D) and f o u r t h p a i r ( p l a t e V I I I , f i g . B) of swimming l e g s same as Small female. F i f t h p a i r of swimming l e g s ( p l a t e X, f i g . A) same as Small female except f o r p r o p o r t i o n a t e l e n g t h d i f f e r e n c e s i n the d i s t a l segment of the exopods as noted i n the r e s u l t s sec-t i o n . A l s o , t h i r d or d i s t a l segment of endopodites e i t h e r w i t h 5 °r 6 setae. T h i s f e a t u r e not c o n s i s t e n t between forms• e.g., one animal may have 6 setae on l e f t t e r m i n a l segment znd 5 on r i g h t . Large females with 6 r a t h e r than 5 setae more f r e q u e n t l y than Small females. For males, 6 setae on d i s t a l segment common but not c o n s i s t e n t . MALE. Prosome ( p l a t e XI, f i g . B) wi t h a n t e r i o r cephalothorax s l i g h t l y more produced than female but not as extreme as small male. M i d - p o s t e r i o r d o r s a l s u r f a c e of cephalothorax a t d i v i s i o n w ith second t h o r a c i c somite not as markedly produced as Small male. Remainder of prosome as f o r d e s c r i p t i o n of Small male and female. Urosome ( p l a t e XI, f i g . B) same as d e s c r i p t i o n f o r Small male, but width to l e n g t h r a t i o s d i f f e r f o r segments 3 and -4-. (See r e s u l t s s e c t i o n . ) Antennule ( p l a t e XI, f i g . B'; same as d e s c r i p t i o n f o r Small male. P a r t i a l f u s i o n between segments 7 and 8 i n males of both forms. Antenna ( p l a t e XI, f i g . B) same as d e s c r i p t i o n f o r Small male. Mandible ( p l a t e X I I I , f i g . A) same as d e s c r i p t i o n f o r Small male and female. M a x i l l u l e ( p l a t e XIV, f i g . A) same as d e s c r i p t i o n f o r Small female. M a x i l l a ( p l a t e XIV, f i g . B) same as d e s c r i p t i o n f o r Large female. M a x i l l i p e d ( p l a t e XV, f i g . B) same as d e s c r i p t i o n f o r Small male and Small female. (Note p l u m o s i t i e s near proximal a r t i c u l a t i o n of second segment i n both forms.) F i r s t ( p l a t e XVI, f i g . B), second ( p l a t e XVII, f i g . D), t h i r d ( p l a t e XVII, f i g . E ) , and f o u r t h ( p l a t e XVII, f i g . F) p a i r s of swimming l e g s same as d e s c r i p t i o n of Small male only-l a r g e r . F i f t h p a i r of swimming l e g s ( p l a t e XVIII, f i g . A) with coxopodite s i m i l a r to Small male. B a s i p o d i t e with spinose process on a n t e r i o r s u r f a c e of d i s t a l a r t i c u l a t i o n near exo-p o d i t e not as conspicuous as i n Small males. Endopodite s i m i l a r to Small male. L e f t exopodite not markedly l o n g e r than r i g h t exopodite as i n Small males; thus l e g s appear n e a r l y symmetrical. De-s c r i p t i o n f o r Small male same as f o r Large male but note pro-p o r t i o n a t e d i f f e r e n c e s d i s c u s s e d i n r e s u l t s s e c t i o n . R i g h t exopodite same as f o r d e s c r i p t i o n of Small male except r i g h t exopodite extends s l i g h t l y beyond a r t i c u l a t i o n of d i s t a l segment of l e f t exopodite. F i r s t 2 segments of r i g h t exopodite markedly l o n g e r than f i r s t segment of l e f t exopodite. PLATE VI a 

Cite

Citation Scheme:

        

Citations by CSL (citeproc-js)

Usage Statistics

Share

Embed

Customize your widget with the following options, then copy and paste the code below into the HTML of your page to embed this item in your website.
                        
                            <div id="ubcOpenCollectionsWidgetDisplay">
                            <script id="ubcOpenCollectionsWidget"
                            src="{[{embed.src}]}"
                            data-item="{[{embed.item}]}"
                            data-collection="{[{embed.collection}]}"
                            data-metadata="{[{embed.showMetadata}]}"
                            data-width="{[{embed.width}]}"
                            data-media="{[{embed.selectedMedia}]}"
                            async >
                            </script>
                            </div>
                        
                    
IIIF logo Our image viewer uses the IIIF 2.0 standard. To load this item in other compatible viewers, use this url:
https://iiif.library.ubc.ca/presentation/dsp.831.1-0093285/manifest

Comment

Related Items